I do like the cathode set-up, but I believe keeping the saber "wireless" may be beyond many folks here (at least in cost).
I would assume that it is done by "machining" a tiny metal lightsaber hilt, using the external "shell" of the hilt as one of the power leads. The other lead would be done possibly through the "power switch" on the saber itself, keeping the two separate (possibly through a tiny rubber gasket.)
I would guess that the inverter is hidden within the figure itself, which is nice, but it does present a danger (as the inverter could theoretically overheat).
The wires would be run through the arm to the hand, which would be configured to have two power leads that would come into contact with the saber hilt at different positions.
All you would need is a 12v power source, and there you would have it (either by battery or wall plug in).
The machining aspect would likely be the hardest thing to accomplish, as most of us don't own a Mini-lathe for metal. I looked at these lathes, but the cost is way too much for the little amount of use it would get from someone like me. I do like the concept of creating tiny precise hilts though.
I ordered a couple of cathodes and will try to post the image against the EL-wire to show the difference in brightness once I get them.
The more options for members, the better.