This is a fairly uninspired idea, but it would solve a problem I have. I sometimes workout to videos (you know - ab stuff, Tae-bo, etc), which is great because it's cheap and I don't have to worry about how I look while I'm doing it, etc.
But I get bored of hearing the same music all the time. So
I change videos and get bored of them, and so on. So. I know that you can press 'shuffle' on your CD player, to get a random mix of songs. Here's what I propose for exercise DVDs.
Have 3 Sections: Warm up, Workout and Cool down. Each section has 3 (or more) versions of itself. By pressing "shuffle" on the DVD player, or more likely selecting it from the DVD options menu itself, since DVD players are not really this sophisticated yet, you will have a randomly chosen workout.
It would have to have the right order, of course - warm up, workout, cool down. But it will all work together, being created by the same people with the same goals. The music (please god) can be varied with each segment too.