Makers of ShapeShifter, the WindowBlinds of OSX
Yup, you can skin Macs, and yes, there are software tools to do it. ShapeShifter http://unsanity.com/haxies/shapeshifter by Unsanity LLC http://www.unsanity.com is a commercial program that enables skinning of the OSX environment, similar to what WindowBlinds does for Windows. Developer Brian Wilson was recently interviewed at skinyourscreen.com http://www.skinyourscreen.com>skinyourscreen.com regarding the Konfabulator/Dashboard issue, the recent press Apple has been receiving due to iPod and Mini sales, as well as their future goals.
Here's the link to the interview: http://www.skinyourscreen.com/server/content.php?article.28