Zork,
Thanks so much.
I got it working, I have my bags and my character bar in the bottom left hand side of the screen and its set to fade on mouse over.
So heres the code if you want the same thing on your UI.

-------------
--bags fade
-------------
local f = CreateFrame("Frame","bag_holder",UIParent)
f:SetFrameStrata("BACKGROUND")
f:SetWidth(300)
f:SetHeight(30)
f:SetBackdrop({
bgFile = "",
edgeFile = "",
tile = true, tileSize = 16, edgeSize = 16,
insets = { left = 0, right = 0, top = 0, bottom = 0 }
})
f:SetBackdropColor(0,0,0,1)
f:ClearAllPoints()
f:SetPoint("BOTTOM",UIParent,"BOTTOM",-230,0);
f:SetPoint("LEFT",-0,0)
f:Show()
MainMenuBarBackpackButton:ClearAllPoints()
MainMenuBarBackpackButton:SetParent(f)
MainMenuBarBackpackButton:SetPoint("BOTTOMRIGHT",bag_holder,"TOPRIGHT",-270,-40)
CharacterMicroButton:ClearAllPoints()
CharacterMicroButton:SetParent(f)
CharacterMicroButton:SetPoint("BOTTOMRIGHT",bag_holder,"TOPRIGHT",-185,-36)
CharacterBag0Slot:SetParent(f)
CharacterBag1Slot:SetParent(f)
CharacterBag2Slot:SetParent(f)
CharacterBag3Slot:SetParent(f)
KeyRingButton:SetParent(f)
TalentMicroButton:SetParent(f)
SpellbookMicroButton:SetParent(f)
QuestLogMicroButton:SetParent(f)
SocialsMicroButton:SetParent(f)
MainMenuMicroButton:SetParent(f)
HelpMicroButton:SetParent(f)
LFGMicroButton:SetParent(f)
local counter = .5
local function fOnUpdate(_,elapsed)
counter = counter + elapsed
if counter > .5 then counter = 0
if MouseIsOver(f) then
f:SetAlpha(1)
else
f:SetAlpha(0)
end
end
end
addon:SetScript("OnUpdate",fOnUpdate)
I hope this bit of code will help someone else out. Put this in your rBars file and make sure you have your bags and character buttons set to show or this won't work.