So, does that mean instead of using the audio tracks you are recording long samples, assigning them to a pad, and using them on midi tracks instead? If so, that's pretty cool because you can save audio tracks for other stuff.
I used to like song mode a lot for composing in my MPC1K. Even if you are using one sequence, I'm guessing you could either have vocals on multiple tracks or on the same track on different pads set to poly mode (I forget if that's the right term on the MPC; the mode that doesn't choke samples). That should allow samples to overlap if the sequence is long enough. Also, I'm pretty sure there is a setting in the bounce to WAV mode that allows you to adjust the tail so that the last sample doesn't get cut off.
Anyway, looking forward to the videos and more info. The Live isn't available in Japan yet, so all this info is good to have before I pull the trigger.