I wish Google would release Picasa for OS X...Google's Picasa does something similar. It has been a while since I last used it, but it does have a collage feature which scatters a bunch of pictures on the desktop. Although it is not directly what you are asking for, you may want to look into it. I thought it was pretty interesting.
Yep.. I made that myself in PS3... I didn't know about Photo Desktop 2 and wanted the multiple pictures posted so I put my creativity hat on..
The desktop for sure is the Apple Store Ginza, by Atreire, only modified with a blue hue, tried to link but safari died on me [win beta], here it isyeah i wanna know about that cover art thing too!
and a link to that wallpaper...