My plan is to use a pair (10w flood and 20w spot, or vice-versa, or maybe twin 10w) of halogen MR16 lights, in the Optronics QH-7CC housing, driven at 14.4V with a NiMH battery. The battery is about $80 on batteryspace.com, the housing $20, lamps $3 ea, and aluminum bar stock free from the corporate junk pile.