Well, all I know is Animanga (this site here) is 
located in Switzerland, in France there is Pico 
et Pina ( http://www.geocities.com/picopina/ ).
I'm living in Germany and there's definitely NO 
cel dealer here. (it's hard to find other 
collectors (around 5 at the moment) 
Well some shops have a few cheap dragon ball 
cels, but nothing you would really buy...

Well, my gallery is online (url at the top), but 
I'm not a dealer, just a poor collector :)