hmmm ive already got the drives and motors from kelling in the states, the motors and drives are the 425 oz-in motor and KL-4030 Bipolar Driver the drive features are ..

* Voltage up to 24 to 40VDC, current output up to 3.0 A
* Selectable resolutions, 1,1/2, 1/4, 1/8, 1/16, 1/32, 1/64
* Suitable for 4,6,8 lead motors
* DIP switch current setting:
0.9A,1.2A,1.5A,1.8A,2.1A,2.4A,2.7A,3.0A
* Over voltage, heat and short-circuit protection

If i did end up gearing the ballscrew with some kind of belt and belt grip was a issue i could devise some sort of roller bearings in between the two pulley wheels so it would wrap the belt more so around the small drive pulley! just a thought, i suppose that all depends on what hight the teeth were on the pulleys and belt.