Rossmusic, have a good look at some tutorials phil flood has put up. He shifts the notes across bar to achieve same effect (as if slowing or speeding up) while BB happilly plays along at same ‘tempo’. It means that beats don’t match visual display while you’re notes are at odd intervals… but it’s the bird in the hand right now.
It’s in two parts and the files got lost (a crash and a site name change?) and were then reposted by Phil , so bear with it… but it could help you… if you use Logic pro… but most DAWs have some sort of time stretching/loop or part sizing ability. I use Cubase and while I haven’t done what Phil is talking about… I know I could.
Tutorial part 1
Part 2