Hey Jürgen,
have you ever looked at the Playtime plugin for Reaper? It adds a clip launcher that is really powerful by using Reaper's API. It seems a bit abandoned, though. I think every clip item on a track gets placed at the beginning of the timeline and then the correspondant items are copied to where they should be when a clip is active. So compared to your approach the first clip of track 1 can play together with the 5th clip of track 2 and so on, you can have different clip lengths, and starting points, tempo detection...
Wouldn't it be possible to use a similar approach for Drivenbymoss or to integrate Playtime? Here in the section automation you can see how Playtime functions could be mapped with the help of automation parameters:
https://www.helgoboss.org/projects/p...toc-automation
I tried once to write a script so I could use modifier keys to also do things like deleting or selecting a clip, but that was to hard for me.
By the way, what's incredibly useful with Playtime for live looping is that multiple clips can be played simultaneously per track. Sadly that's impossible with Live or Bitwig.
So overdubbing is dead easy.
I made a demo video for that a while ago (LED feedback is already integrated for a bunch of controllers):
https://www.youtube.com/watch?v=DomZafMSfE0