I might be misunderstanding the idea, but I don't think it addresses the original problem that wires can't connect the two parts of something that rotates in a single direction.

I think what he means is having the second motor act as a generator driven by the first motor (maybe with some geared arrangement to have the generator shaft rotate at a different rate from the body), so that the resulting power can be used for the rotating electronics.

Sorry if I'm being dense, but the second motor (the generator) must stay stationary relative to the first motor to do the generating. Which means that the generator is on the same "plane" as the power source. The problem all the solutions are trying to solve is how to transmit power from one plane to another rotating plane, because physical wires can't do it without getting twisted up. So if the generator is on the same plane as the power source, then it can't contribute to solving the problem.

It shouldn't have to stay stationary I think? As long as the shaft rotates at a different rate to the body, there should be some power generated. That's why I mentioned the need for gears.

Overall though it's certainly not going to be good enough to justify the complexity compared to either slip rings or wireless transmission.

I think I get it now. Maybe the main rotor rotates at 6,000 rpm, the geared assembly has a 10-1 reduction so it rotates at 600 rpm (giving the LEDs 10 fps), and the 5,400 net rpm difference is used to generate power. Yes, maybe that would work.