I am waiting to see what the G5 looks like before I decide on the skins. I like the concept, especially if Apple doesn't change the case for the G5 (initial release).
I sent feedback to the skins people letting them know that they need to have something for the front of the computer as well as the sides. I have my G4 tower sitting under my desk, where I only see one side and the front. If they don't offer something for the front to tie the designs together, I won't really consider them.
I should check and see what kind of paint and such to use on the sides of the Mac, so that I too can pull out the old airprush and do some of my own. Even better, get ahold of people that work with carbon fiber and get them to make a few sheets to go over both sides (make the latch usable too) as well as the front. If nothing else, you can get a very thin sheet, heat it up a little so that it is flexible, and use that on your own.
Good concept, but the execution and designs need work.