I would like to know if there is a way to programmatically arrange desktop windows similar to Expose in Cocoa.
The best I can think of off the top of my head is this (somewhat clumsy, and doesn't continue to show moving content, but should work):
Alternately, the same trick but instead of using real windows, make one screen-sized transparent window and move CALayers around in it.
Good luck! This is definitely a tricky thing to do well.