Where I'd use longer contact surfaces.
Oh well. If you put a magnet in the hub and a hall sensor on the chassis or vice versa then you have a good way to know orientation of the wheel. Or you can go with optical.
Still, how you get power to the leds from the controller(s)? Will you put batteries -in- the wheels? You see that you will need contacts if power and controller are in the chassis unless you do something really wild?
ps, maybe not so wild -- if the wheels have not leds but translucent plastic then it could be lit by light on the chassis. There are ways and then there are ways.