I've been playing this for awhile. (Unfortunately I had start over due to lack of play.)
Anyways, KHInsider has their own Kingdom Hearts RPG called Inferno. If you want to play go to the link below and create an account, then go to RPG and make a character and start playing.
My name will be Hauser.
http://forums.khinsider.com/
If you know about this already, well, good for you.