I hadn't seen this thread previously but am very happy to see it now as I've lately been trying to find a good controller solution for the RYTM.
I'm really liking EC12. Honestly I wouldn't even mind a Launchpad-sized controller that combines the MX12 and EC12. Currently I use a Launch Control XL for my RYTM, but it's not enough channels and not enough knobs. I've been on the verge of picking up the smaller Launch Control to use just for delay/reverb sends, freeing up the knobs on the XL as voice parameter controls. On the XL I flip-flip between using the faders as volume or performance controls. So EC12 + MX12 (if crammed into a Launch Control XL size square) could allow 6 encoders, 2 buttons, and 1 fader per channel. That would be so helpful.
But I know you've got to keep in mind selling these to a broader audience, so I'll pair the 2 controllers myself if I need to