Has anyone tried using one of these or something similar?

http://www.polysci.com/SlipRings/slipring.html

We use them at work on wind turbines. Moog units cost thousands of dollars though. Some on here have made their own or used a rotary telephone jack. I assume you are looking at them for turret rotation.
Perry

they have some little ones that are like 12 channels and a half inch in diameter plastic.

I was looking at teh slip ring capsules, They seem to be what the tamiya pershing needs to have smooth rotation, heck I think all tam tanks can benifit from this. Just wonder how much they would cost.

I thought about similar the other day as a matter of fact.

Without delving into the problems associated with space, I imagined a plastic ring mounted to the underside of the turret, with the requisite number of concentric copper strips adhered to the ring.

Some newer vehicles (some minivan sliding doors at least) use spring loaded metal pins mounted in the door, that contact a plate mounted in the door frame, that transfer power when closed. Mounting one of those under the envisioned turret ring would seem to be a pretty easy endeavor, however the size of these auto units, in particular spacing between the pins, may be too large for 1:16 scale tanks, at least the ones I've seen. Perhaps smaller are already in use and I just haven't seen them?

It would probably be far less costly than what is shown above, but labor intensive, IF the components could be made/made to fit.

Your idea has been done or at least mostly done. See this: http://www.rcuniverse.com/forum/m_5435477/tm.htm

Anyone contact polysci to see if they make somthing that would work and at what cost? It seems to be a lower profile than the styrene idea.