I'm not good on voice guessing, because a lot of the time, someone you'd never think about is casted to voice, and casted well. If they were to make a live production of it...Rasitlin...I can't think of any big-timers that would really suit the role, BUT, one guy I'd seen in a show came to mind.
Now, I haven't read MUCH dragonlance, but in the series I was reading, Raistlin was somehow sick and weakened throughout the thing, so bearing that in mind, I thought of this one guy...did you ever watch "24" series 1? I dunno the characters name, but towards the beggining when Kim and her friend are kidnapped by the two guys in the van?
The one guy that's kinda reluctant about it all, and ends up helping the girl escape. He looks kinda dark and a lil' miserable...I can see him working in the role. The actors name is Daniel Bess.
http://www.danielbess.net/
The pics on that site don't really show the qualities I'm talking about, but when he looked all junked up in 24, he looked as though he'd suit the part just fine.