The switch to a 24v PSU more than doubled the top speed from 200mm/sec to 500mm/sec with no other mechanical changes required. Acceleration has also been increased from 3000 to 5000.
We had to stop at 500mm/sec or we ended up violating the step length requirements of the DRV8825's of 1900us.
We will never approach the stepping limits of the BBB/Machinekit itself unless we decide to do some radio broadcasts.
Acceleration will probably still be tuned back down to avoid excessive vibration during stitching.
We now need some better acoustic dampening/isolation, but I'm back to being happy with Nema 23 steppers again.