This tweak adds a transparent top menu bar to Singularity's Gemini skin. To use it, copy the "colors.xml" file to ovewrite the one found in your Singularity installation directory in /opt/singularity-install/skins/gemini. 
Code:
<?xml version="1.0" encoding="utf-8" standalone="yes"?>
<settings version = "101">
<!-- WINDOWS -->
<TitleBarFocusColor value="0, 0, 0, 0" /> <!-- Focused window title bar highlight, no equivalent for unfocused windows -->
<FloaterFocusBorderColor value="0, 0, 0, 50" />
<FloaterUnfocusBorderColor value="0, 0, 0, 80" />
<FocusBackgroundColor value="33, 33, 33, 255" /> <!-- Background color of focused floaters -->
<DefaultBackgroundColor value="33, 33, 33, 192" /> <!-- Background color for unfocused floaters -->
<ColorDropShadow value="0, 0, 0, 64" /> <!-- The drop shadow behind windows and menus -->
<DefaultHighlightDark value="26, 26, 26, 255" />
<DefaultHighlightLight value="66, 66, 66, 255" />
<DefaultShadowDark value="26, 26, 26, 255" />
<DefaultShadowLight value="0, 0, 0, 255" />
<!-- LABELS -->
<LabelDisabledColor value="255, 255, 255, 30" />
<LabelSelectedColor value="255, 255, 255, 128" />
<LabelSelectedDisabledColor value="255, 255, 255, 80" />
<LabelTextColor value="255, 255, 255, 90" />
<!-- LOGIN -->
<LoginProgressBarBgColor value="255, 255, 255, 255" />
<LoginProgressBarFgColor value="255, 255, 255, 255" />
<LoginProgressBoxBorderColor value="0, 30, 60, 0" />
<LoginProgressBoxCenterColor value="0, 0, 0, 200" />
<LoginProgressBoxShadowColor value="0, 0, 0, 200" />
<LoginProgressBoxTextColor value="255, 255, 255, 255"/>
<!-- BUTTONS -->
<ButtonLabelColor value="255, 255, 255, 128" /> <!-- Text labels for buttons, like the "OK" text -->
<ButtonLabelSelectedColor value="255, 255, 255, 255" />
<ButtonLabelDisabledColor value="255, 255, 255, 66" />
<ButtonLabelSelectedDisabledColor value="255, 255, 255, 66" />
<ButtonSelectedBgColor value="62, 62, 62, 255" />
<ButtonSelectedColor value="255, 255, 255, 255" />
<ButtonUnselectedBgColor value="62, 62, 62, 255" />
<ButtonUnselectedFgColor value="255, 255, 255, 255" />
<ButtonBorderColor value="239, 156, 0, 255" />
<ButtonFlashBgColor value="255, 255, 255, 128" />
<ButtonColor value="255, 255, 255, 128" /> <!-- Blended with button art, usually left as opaque white -->
<ButtonImageColor value="255, 255, 255, 128" /> <!-- Blended with button art, usually left as opaque white -->
<!-- SLIDERS -->
<SliderDisabledThumbColor value="0, 0, 0, 255" />
<SliderThumbCenterColor value="200, 200, 200, 255" />
<SliderThumbOutlineColor value="255, 255, 255, 255" />
<SliderTrackColor value="255, 255, 255, 255" />
<!-- TEXTFIELDS -->
<TextBgFocusColor value="11, 11, 11, 255" /> <!-- Text field background when receiving input (focused) -->
<TextBgReadOnlyColor value="11, 11, 11, 160" /> <!-- Text field background when read-only -->
<TextBgWriteableColor value="11, 11, 11, 80" /> <!-- Text field background when not receiving input (unfocused) -->
<TextCursorColor value="128, 128, 128, 200" />
<TextFgColor value="255, 255, 255, 222" />
<TextFgReadOnlyColor value="255, 255, 255, 80" />
<TextFgTentativeColor value="255, 255, 255, 80" />
<TextEmbeddedItemReadOnlyColor value="255, 255, 255, 80" /> <!-- i.e. About Land name that you don't own -->
<TextEmbeddedItemColor value="0, 255, 128, 255" />
<TextDefaultColor value="255, 255, 255, 222"/>
<TextLinkColor value="144, 165, 208, 255"/>
<TextLinkHoverColor value="255, 255, 255, 255"/>
<!-- LISTBOXES -->
<ScrollBgReadOnlyColor value="33, 33, 33, 80" />
<ScrollBgWriteableColor value="33, 33, 33, 80" />
<ScrollBGStripeColor value="100, 100, 100, 25" />
<ScrollDisabledColor value="33, 33, 33, 204" />
<ScrollSelectedBGColor value="222, 222, 222, 150" />
<ScrollSelectedFGColor value="255, 255, 255, 255" /> <!-- Text color -->
<ScrollUnselectedColor value="222, 222, 222, 150" /> <!-- Text color -->
<ScrollHighlightedColor value="222, 222, 222, 80" /> <!-- Hover color -->
<ScrollbarThumbColor value="66, 66, 66, 80" /> <!-- Scroll bar-->
<ScrollbarTrackColor value="10, 10, 10, 80" /> <!-- Scroll bar background-->
<DefaultListText value="255, 255, 255, 255"/> <!-- We are replacing all the hardcoded black text with this color so we can make skins with white text on dark background -->
<!-- MENUS -->
<MenuBarBgColor value="33, 33, 33, 128" />
<MenuBarGodBgColor value="33, 33, 33, 255" />
<MenuNonProductionGodBgColor value="0, 128, 0, 255" />
<MenuNonProductionBgColor value="128, 0, 0, 255" />
<MenuDefaultBgColor value="33, 33, 33, 255" />
<MenuItemDisabledColor value="125, 125, 125, 75" /> <!-- Menu text color; also text color for pie menus and treeviews (like Inventory) -->
<MenuItemEnabledColor value="255, 255, 255, 255" /> <!-- Menu text color; also text color for pie menus and treeviews (like Inventory) -->
<MenuItemHighlightBgColor value="80, 80, 80, 200" />
<MenuItemHighlightFgColor value="255, 255, 255, 255" /> <!-- Highlighted menu text color; also treeview node selection highlight -->
<MenuPopupBgColor value="33, 33, 33, 255" />
<!-- PIE MENUS -->
<PieMenuBgColor value="33, 33, 33, 128" />
<PieMenuLineColor value="0, 0, 0, 128" />
<PieMenuSelectedColor value="255, 255, 255, 128" />
<!-- TOOLTIPS -->
<ToolTipBgColor value="33, 33, 33, 255" />
<ToolTipBorderColor value="11, 11, 11, 255" />
<ToolTipTextColor value="255, 255, 255, 255" />
<!-- NOTIFICATION POP-UPS -->
<NotifyBoxColor value="66, 66, 66, 255" />
<NotifyTextColor value="255, 255, 255, 128" />
<NotifyCautionBoxColor value="254, 209, 118, 255" /> <!-- the background color of caution permissions prompts -->
<NotifyCautionWarnColor value="0, 0, 0, 255" /> <!-- the foreground color of the special title text in caution permissions prompts -->
<GroupNotifyBoxColor value="66, 66, 66, 255" />
<GroupNotifyTextColor value="255, 255, 255, 128" />
<!-- CHAT AND IM HISTORY TEXTBOX COLORS -->
<ChatHistoryBgColor value="0, 0, 0, 0" />
<ChatHistoryTextColor value="255, 255, 255, 255" />
<IMHistoryBgColor value="0, 0, 0, 0" />
<IMHistoryTextColor value="255, 255, 255, 255" />
<!-- IN-WORLD SELECTION -->
<SilhouetteParentColor value="255, 255, 0, 255" />
<SilhouetteChildColor value="32, 106, 196, 255" />
<HighlightParentColor value="171, 212, 245, 255" />
<HighlightChildColor value="171, 212, 245, 255" />
<HighlightInspectColor value="255, 0, 255, 255" />
<!-- EDIT MODE GRID -->
<GridFocusPointColor value="255, 255, 255, 128" />
<GridlineColor value="255, 255, 255, 255" />
<GridlineBGColor value="235, 235, 255, 200" />
<GridlineShadowColor value="0, 0, 0, 80" />
<!-- PROPERTY LINES -->
<PropertyColorAvail value="0, 0, 0, 0" />
<PropertyColorGroup value="0, 184, 184, 102" />
<PropertyColorOther value="255, 0, 0, 102" />
<PropertyColorSelf value="0, 255, 0, 102" />
<PropertyColorForSale value="255, 128, 0, 102" />
<PropertyColorAuction value="128, 0, 255, 102" /> <!-- Match the color on the world map -->
<!-- Icon Enable/Disable -->
<IconEnabledColor value="255, 255, 255, 255"/>
<IconDisabledColor value="255, 255, 255, 200"/>
<!-- MAP -->
<MapAvatar value="70, 255, 70, 255" />
<MapFriend value="255, 210, 150, 255" />
<MapLinden value="0, 128, 255, 255" />
<MapMuted value="110, 110, 110, 220" />
<!-- RADAR -->
<RadarAvatar value="255, 255, 255, 255" />
<RadarFriend value="70, 128, 70, 255" />
<RadarLinden value="0, 0, 128, 255" />
<RadarEstateOwner value="204, 102, 10, 255" />
<RadarMuted value="33, 33, 33, 255" />
<RadarTextChatRange value="255, 66, 66, 128"/>
<RadarTextShoutRange value="255, 255, 66, 128"/>
<RadarTextDrawDist value="66, 153, 66, 128"/>
<RadarTextYoung value="255, 66, 66, 255"/>
<!-- SPEAKERS -->
<SpeakersInactive value="76, 76, 76, 255"/>
<SpeakersGhost value="255, 0, 0, 255"/>
<!-- MINI-MAP -->
<NetMapBackgroundColor value="0, 0, 0, 77" />
<NetMapYouOwnAboveWater value="0, 255, 255, 255" />
<NetMapYouOwnBelowWater value="0, 200, 200, 255" />
<NetMapGroupOwnAboveWater value="255, 0, 255, 255" />
<NetMapGroupOwnBelowWater value="200, 0, 200, 255" />
<NetMapOtherOwnAboveWater value="60, 60, 60, 255" />
<NetMapOtherOwnBelowWater value="30, 30, 30, 255" />
<NetMapThisRegion value="255, 255, 255, 255" />
<NetMapLiveRegion value="204, 204, 204, 255" />
<NetMapDeadRegion value="255, 128, 128, 255" />
<NetMapFrustum value="255, 255, 255, 70" />
<NetMapFrustumRotating value="255, 255, 255, 100" />
<!-- HELP WINDOW -->
<HelpBgColor value="200, 209, 204, 255" />
<HelpFgColor value="0, 0, 0, 255" />
<HelpScrollTrackColor value="183, 184, 188, 255" />
<HelpScrollThumbColor value="80, 96, 124, 255" />
<HelpScrollHighlightColor value="115, 132, 155, 255" />
<HelpScrollShadowColor value="0, 0, 0, 255" />
<!-- MISC -->
<AvatarNameColor value="251, 175, 93, 255" /> <!-- Text color of avatar nametags -->
<FocusColor value="255, 255, 255, 20" /> <!-- Color of the glow around UI controls with keyboard focus -->
<FloaterButtonImageColor value="255, 255, 255, 80" /> <!-- The floater buttons (like the close box) are white images that receive this color. -->
<ButtonCautionImageColor value="255, 255, 255, 255" /> <!-- Match the caution dialog buttons to the default -->
<HealthTextColor value="255, 255, 255, 255" />
<MapAutopilotColor value="255, 255, 255, 255" />
<ContextSilhouetteColor value="255, 255, 255, 255" /> <!-- For "context" highlighting, i.e. pie menu -->
<ScriptBgReadOnlyColor value="100, 100, 100, 255" />
<ParcelTextColor value="144, 165, 208, 255" /> <!-- Parcel name on menu bar, normal state -->
<ParcelHoverColor value="255, 255, 255, 255" /> <!-- Parcel name on menu bar, hover state -->
<TimeTextColor value="255, 255, 255, 255" /> <!-- SL Time on menu bar -->
<BalanceTextColor value="255, 255, 255, 255" /> <!-- Linden dollar balance on menu bar -->
<HealthTextColor value="255, 255, 255, 255" /> <!-- Damage meter text on menu bar -->
<GroupOverTierColor value="255, 255, 255, 255" /> <!-- Warning text in Group Info window -->
<FilterBackgroundColor value="0, 0, 0, 255" /> <!-- Matching region of Inventory search text -->
<FilterTextColor value="255, 255, 255, 128" />
<InventoryItemSuffixColor value="128, 128, 128, 255" /> <!-- "worn", "no modify", etc-->
<InventorySearchStatusColor value="255, 255, 255, 128" />
<ComboBoxBg value="11, 11, 11, 255"/>
<ConsoleBackground value="0, 0, 0, 255" />
<FolderViewLoadingMessageTextColor value="255, 255, 255, 128"/> <!-- "loading..." in the inv -->
<InventoryBackgroundColor value="11, 11, 11, 80"/>
<SHMediaTickerOscillatorColor value ="0, 0, 0, 191"/>
<!-- Alert box colors -->
<AlertBoxColor value="33, 33, 33, 255" /> <!-- Warnings floaters, like when returning objects -->
<AlertTextColor value="128, 128, 128, 255" />
<AlertCautionBoxColor value="254, 209, 118, 255" /> <!-- Background color of caution alerts -->
<AlertCautionTextColor value="0, 0, 0, 255" /> <!-- Foreground color of the special title text in caution alerts -->
<!-- Multi sliders, as in the sky animation setting -->
<MultiSliderDisabledThumbColor value="0, 0, 0, 255"/>
<MultiSliderThumbCenterColor value="183, 184, 188, 255"/>
<MultiSliderThumbOutlineColor value="0, 0, 0, 255"/>
<MultiSliderTrackColor value="30, 30, 30, 255"/>
<MultiSliderThumbCenterSelectedColor value="255, 50, 50, 255"/>
<MultiSliderTriangleColor value="255, 255, 50, 255"/>
<!-- LSL colors -->
<LSLFunctionColor value="102, 217, 239, 0" />
</settings>