I am installing bowfishing lights on my boat and using high pressure sodium and metal halide lights powered by a generator. These are brighter than the 110v halogen work lights you can get anywhere, and completely blow away any of the off road lights. They can also be run from a power inverter connected to your electrical system.
Sams is selling a 500 watt 12v to 110v power inverter right now for about 25 bucks.
Since you will be limited to 500 watts if you use this inverter I am comparing the lights in 250 watt fixtures assuming you would run 2 of them.
KC Hi-Lites biggest light is a 130 watt Halogen, they produce about 2,600 lumens and sell for about 100 bucks.
250 watt Halogen work lights produce about 20 lumens per watt or 5,000 lumens and sell for 10-12 bucks.
250 watt Metal Halide fixtures produce about 100 lumens per watt, or 25,000 lumens and sell for about 150-175 bucks.
250 watt High Pressure Sodium fixtures produce about 110 lumens per watt, or 27,500 lumens and sell for about 150-175 bucks.
If I was going with the MH or HPS I would get cheaper, smaller fixtures than the 250 watt and spread them out, or just use 2 and save some bucks and electricity.
-John