Addendum:
-- a bunch of the Expert Sleepers units might be candidates, but I'm not sure about the "1 at a time" interface issue noted above. Maybe what Expert Sleepers mean by "interface" is not the same as what live means when selecting my RME UFX as the single "interface"...
-- when it comes to trigger / gate to MIDI, it looks like there are some options including Doepfer, Ladik, VPME
-- CV to MIDI there are some other options. ADDAC 222/221 could be usable? Befaco VCMC and/or CV thing? Delptronics CV to MIDI ("coming soon")?
So those are some of the candidates I've seen so far. But as the note says above, I would LOVE to hear suggestions from people who have succeeded with this kind of connection into DAWs for songwriting (or similar) purposes. Obviously there's a lot that could go wrong, and anything less than a solid and low-latency connection would be a recipe for frustration.
Thanks for any suggestions you may have!