Cels Forum

For Ifuritas from El Hazard and Project Ako cels - both 
anime-cel.com and Anime Taro had some in very recently; check there first.  Anime Shop Pocket has some Plastic Little cels.  And for production Evangelion cels, Anime Taro had about 5 of them in Feb so probably all gone from there and don't know of anyone else for those.

Hope this helps a little,
Melissa