Try
www.wincustomize.com - loads there.
( Bob Todd ask me shit: formspring.me/BobTodd, Tue 10 Jun 2008, 10:53, archived)

Ooh actually Caewan's bus driver linked him to a good site, which I had a look at when he linked it to prodge...
www.opacity.us/

Edit: Aha, I'm using this now:
www.opacity.us/extras/wallpapers/metropolitan_open_screens_1280x1024.jpg
( ClanSoul, Tue 10 Jun 2008, 10:54, archived)