Cels Forum

They only sell in bulk outside Japan (you can click on the
for english speaking customers button at the top of there
page)  They do not sell individual cels or items outside
Japan though (too bad since they have some nice stuff!) 
Anime Galaxy used to be able to get you stuff for a finders
fee but I believe the person that is runns that page is
leaving Japan so I don't think they will be able to do that
anymore.