Kakure Wild
Nephrite (now closed)
Retonomiyako
Fanart Sites That Have Specifically Denied Permission
Aidma
Kumoji
Fanart Sites That Have Not Responded to My Requests
Reimyou
C-three
PochinokoPro
Mr. Randomness
candy*store
Probably some others that I've forgotten. Note to self: ask Keroyon for permission.
Fanart Sites That I Know Don't Give Permission
A2 (or so I've been told, although the text on the index page makes it seem like she's willing to give permission if asked)
Israk