I fully agree with commutating the power rather than the LED wires. There are lots of good reasons for this, not the least of which is that with most designs there will simply be too many LED wires. That said, I have found that switching regulators are a tremendous asset for this kind of situation. Not only do they allow you to use a higher supply voltage, and thus reduce the current required through the slipring system, but they have incredible filtering capabilities. In a quick bench test I found that a TI 78HT305, with its 20 kHz switching speed, provides clean 5VDC output from a 24VDC supply when fully loaded even when the input drops to 8V 3600 times a second. Combined with a few other techniques, such as redundant brushes and large capacitors in the right places, you can easily end up with a supply reliable enough to drive a microcontroller and its support hardware from.

For more details, take a look here:

http://www.mech.northwestern.edu/courses/4.../clock.htm

--Sasha Jevtic