I once arranged an ambient track (= song) by muting/unmuting channels “live” while recording the output to tape. Then I played my tape and arranged the track following the live muting of my tape (is this understandable?).
It’s this that I want to be able to record.
I’m not sure, but I think Cubase VST has this.
(ack, I HATE its interface)
 Ofcourse, this would be an option of the in-progress (?) mixing window.
If you can pull it off, please don’t forget live effect param changes also.