It strikes me as a bad idea to perform this with a play-along CD, as it negates all of the interactions that make it a musically satisfying experience. That said, you could try SmartMusic--I think that Creston is available there. You would bring a laptop to the jury and plug into the stereo system. At least (if you use a mic) it could follow your tempo changes.
Good luck!
JR
Good luck!
JR
