It’s weekend…
I would be happy with something simple like this already. A new section at the inspector allows to hold clips. Just drag a part/event to a cell to get it looped from the part/event start to end. You can adjust the part boundaries in the editor. While a clip is looping the parts/events on that track get disabled, indicated by the gray color.
This new section is available for audio, midi and instrument tracks.
The new controller API allows to start/stop the clips. For more fun you can change the color of each clip. This is also sent to the controller to illuminate the pads accordingly.
Advanced: record the free style jam with the clips to record-enabled tracks.
For most fun, the clips are available as a Mixer Rack.
I would so much love this kind of workflow. If you don’t need it, hide the clips section.
For simplicity all clips are the same in this example…