Cels Forum

You'll probably have better luck at the two sites that 
Rob suggested, but you might also try:

Planet Anime (1 for sale)
http://www.NeoSoft.com/~planet/collect/cels_uw.htm

Anime Access (1 for sale)
http://www.tiac.net/users/snowdog/

That's all I can remember off hand.  

     Chad Kawakami
     belldandy@cheerful.com