I've had a lot of interest about the Baghira Desktop Theme that I have been using in Linux lately. They have improved Baghira quite a bit since the project was started. Here is a screenshot I took last year of my desktop. Here is my current desktoprunning the latest version of Baghira. And here is my my desktop in action. If you would like more information on how to make your linux desktop look like MacOSX, visit the official Baghira project website.