Thanks, everyone. I've looked into all of your suggestions.
Headrush was a bit overkill. I'd like to keep it pretty simple and live.
Singular sound doesn't seem to be really out there yet.
The higher level Boss stuff is possible but the footprint and price are pretty big.
It's frustrating because two RC1s are about 95% of the way to what I'd like. I can set the external footswitches next to each other to stop the loops at the same time. So all that's really lacking is a way to start them simultaneously... something I'll do on 1-3 songs out of a 40 song show.
I'm very new to loopers... and acoustics, got into the duo thing accidentally, and was hoping there would be something out there I wasn't aware of that was NOT a full-featured, programmable, pre-recorded, quantized, high-end looper. Preferably for $400 or less.
Ideally, these six buttons would be it:
1. Loop1 record/playback
2. Loop1 stop/erase
3. Loop2 record/playback
4. Loop2 stop/erase
5. Loop2 undo/redo
6. Both combined-stop/combined-restart
I may just be too picky.