I'd like to see a Treadmill and Stationary bike DVD. It could be a 2 separate workouts with a premix that has you jumping off and rotating between the two pieces of equipment like a circuit.
Tracy Staehle has one out now and I like it but I think Cathe would be even better. She could also have a premix where you can mix in weight work or body weight circuits.
I had to laugh at this b/c it's so true. It'd either be plyo or she'd come up with something equally as evil that you did while still on the treadmill or bike!