Well, the happy technical news is that Arduino Leonardo is actually compatible with Teensyduino using TeeOnArdu. 

So I made midi stepper motors today. I used them here with a QuNeo, and the pressure controls the speed.

Well, to achieve that I could use gear dc motors and it would have been faster to program. I assumed that the torque is higher at slow speed with a stepper. But, really, I do prefer the look of them, and mostly, I think the sound of them works better with what I am going to do. And as it is all about sound, so, that is important.