We're using the ring lights from SuperbrightLeds.com. I think these are the same the one AndyMark had for FIRSTChoice. They run on 12 volts, draw very little current and make the retroreflective tape light up like a green searchlight.
The model we have is the AE60-G15; 15 green leds in a 60mm diameter ring which fits around the camera lens.
We got 2 for about $20 shipped. They arrived in Oregon three days after ordering.
Specs are
here.