variable V power supply

Hi,

The recommended power supply for gecko, camtronics, etc motor drives
are unregulated power supply. Is there anything against the use of
regulated power supply other than cost considerations?

Is it advisable to use variable voltage power supply to power these
motor drives? Has anyone ever used variable voltage power supply to
power these drives? Anyone has any plan/diagram/source for a variable
voltage power supply that can drive these with sufficient capacity
for any motors likely to be used for a Sherline or equivalent system.?

Thanks

Peter