There are already some threads on this, like this one
http://www.chiefdelphi.com/forums/sh...t=cim+impeller
I don't know if you've tried searching, but you can usually find things more quickly that way than by posting and waiting for a reply. Sometimes you'll have to try using different search terms, and sorting through a bunch of irrelevant stuff, but it is almost always worth it.
As for attaching a CIM to a roller... presumably a ball magnet type roller... I'm not sure how many teams are using CIM's to do that. We are using the FP motor with a Banebots P60 transmission, and have machined the roller to directly accept the output shaft of the tranny, so it both supports one end of the roller AND turns the whole thing at the same time.
No reason you couldn't do that with a CIM, I suppose... but it might be a bit fast.
I think you'll also find that we had the option of ordering some nice drive belts as part of the KoP this year.
Good luck figuring out some solutions.... and with your searching!
Jason