Hi Steve,
why don't you check out Band in a Box, there's a forum.
Hey, they even offer you your money back if you don't like it.
You can record your backing tracks as audio files.
All you need is some sort of a keyboard to play along with.
The software has Real Tracks, ie real guitar strums, real guitar picking, real drums & bass. Real piano.
The realtrack style library is growing all the time.
Just have a listen to the demo's & talk to some of the muso's who use it for gigging, & a couple of them that I know of even use it in a studio.

The forum guys over there are really helpful. Doesn't hurt to ask.