Probably not cheap but someone at a research company works with electrical muscle sensors and hooked it up to space cadet on Windows. I tried it about 20 years ago. I don’t think anything came of it. I basically twitched the upper part of my shoulders to control the flippers. It translated the electric signal to control the muscle into a switch closure.
(Note: I am NOT disabled from this perspective but got a chance to be in someone’s shoes who might be)
You are onto something here….keep going.