The Marquee Line (just shows StarTip's version) demos background colors with a random color. This line is disabled by default and serves as an example of using marquee settings.

diff --git a/Modules/UnitTooltip/UnitTooltip.lua b/Modules/UnitTooltip/UnitTooltip.lua
index 3de8ebf..354de07 100644
--- a/Modules/UnitTooltip/UnitTooltip.lua
+++ b/Modules/UnitTooltip/UnitTooltip.lua
@@ -379,7 +379,8 @@ end
         update = 1000,
         speed = 200,
         direction = WidgetText.SCROLL_LEFT,
-        dontRtrim = true
+        dontRtrim = true,
+	colorL = "return random(), random(), random(), 1"
     },
     [17] = {
         name = L["Memory Usage"],