I had a double post and edited it out probably at the same time you posted. :)

I made a small wood router years ago with 1/4" wide belts and size 17 steppers that had an area of about 12 x 12 inches and they worked very well. the spindle was a model plane brushless motor with a small fan on top to keep it cool while it spun. I didn't notice any stretch on the belts and probably wouldn't with the small motors.