Rich,
I have a large stepper driven by a 68 volt supply and a 3.6:1 timing belt reduction, and I get 1000 rpm at the spindle using 32 microsteps with no problem. It is likely not as good as a vfd or servo drive, but it will allow me to turn and machine a part without refixturing it. I can turn a part now as long as I simply program enough turns to match the X travel, but then it unwinds to get back to zero.