I don't know the kind of TF you want to comission, and I don't know if you will like their artstyle, but these guys are all good B&W artists that know how to do transformations of some kind and also do NSFW stuff. Also they are close to manga artstyle, and I'm sure they can imitate it.
http://ayayanagisawa.deviantart.com/
http://n647.deviantart.com/
http://h-panda.deviantart.com/
http://jadenkaiba.deviantart.com/
http://onatart.deviantart.com/
http://nathan123qwe.deviantart.com/ (this one is special, it is the manager of a group of artists, some of them know how to draw manga...so stick to those)