plate-of-shrimp Also brings up the question of stomp switch pedalboards, have not looked to see what's out there.
I know there are MIDI boards out there. I played with a Behringer FCB1010 using a USB-Midi converter in Rakarrack on a laptop. It would probably take some coding to pipe the USB-Midi device into Bela, but if you got that working then it would open up a lot of possibilities for HW controllers.
Another idea i have tossed around is I have an Acer Spin5, which is plenty of screen to support a nice control interface, and is trivial to get MIDI messages through the standard Alsa driver. The control interface including control to a HW MIDI controller via USB in the laptop could send messages to Bela via OSC.
I would think a tablet with a USB port could be used in the same way. For that matter a Raspberry pi could be used to bridge the MIDI->USB->Network interface and then you could turn any HW MIDI controller into a HW->OSC controller.
Well there's some brain dump 😉 .