My initial tests show that a "bumper car" style overhead power pick-up may be difficult to reliably deploy for a micro-RC car. There are lots of "dead spots" where the car stops picking up power. I realize though that the optimal pick-ups should be made of stainless steel wire, which should be available for lure tying at Gander
I found a manual for a real overhead pick-up bumper car. They have a quite sophisticated floor pick-up involving a steel brush wheel.
In addition to the overhead power pick-up, there are bumper cars with floor pick-up power system (look at bottom floor picture). Evidently there are stripes of power and ground metal lines on the floor, and there must be some kind of array of electrodes picking up the power and diode-steering it to the engine. Alternatively, the use of AC power could simplify the situation.
Another option is inductive power transfer (IPT), but I'm concerned that it may interfere with the RC radio commands and/or the RF video coming from the car camera.