@chapelierfou: No worries and really thanks for your interest.
Before you dig in though, I’ve had a sort of embarrassing realization. The reason I would like this feature is because I’d like to record some automation envelopes where I’m using the arc to detune a clip sample (and get a Transpose envelope as a result). However, it looks to me like you can’t record automation of clip sample parameters at all? I assumed you could but haven’t been able to. (I can draw envelopes using breakpoints in the Envelopes Box in the Clip View but can’t seem to record interactions with the detune or transpose controls.)
It seems like this just may not be possible? 
This is a great idea. Probably not a way to solve the problem as I posed it since I don’t think even MIDI can be mapped to control of sample detune (happy to be wrong about that though!) but it would be great for another approach where I capture detune info in a midi stream as pitch bend messages. Maybe a variation on knobs, updated to not require push buttons? Otherwise, it’d be really neat if your patch could optionally map to midi CCs. That would make it super flexible. (And the UX is really great BTW!) @chapelierfou: if you’re looking to play with this patch, maybe that’s a more fruitful angle? (No pressure obviously!)
Thanks a million to you both for the ideas so far and in advance for any more!