Check the new xModules, which support the xPaintClass at ls-universe.info!
Then you can have different AlphaTransparency for every element. Icons, Text, Backgrounds, Overlays, ...
And much more

The come without docs in the package, check xDocs.ls-universe.info for informations.

But keep in mind that you have to change several important settings!
It's OK, if you want to make your personal theme, but not if you plan to release it the next time :O

Try it, it's the future!

THEY ARE STILL NOT OFFICIALLY RELEASED AND IN BETA STATE!