I could see this working quite well, actually, if you can get a cheap source. A friend of mine worked with an LED supplier-- he had an FJ Cruiser, and had 3 48"x4", 2 18"x4", and a 4"x4" LED Light Bars... he had to run a dual battery system, but it was surprisingly efficient. They all used CREE 3w LEDs, which all put out about 150 lumens each.

The ones that are cheap have pretty cheap LED's, and aren't super poewrful in comparison, and the ones with nice LED's will cost you.

For lots of continuous light cheaply, I think CFL's are they way to go. There's a bunch of companies that make light stands/adapters with standard E26 sockets, or you can use the cheap $5 clamp on work lights. 85 watt CFLs will put out light equivalent to about a 300 watt halogen flood, and cost $15-$20 a pop. No inverter needed.

EDIT: In fact, I just checked eBay, and there are specific kits, with stands, umbrellas, sockets, and 85w CFL's for about $50. Much fancier than my 85w CFL, duct tape, work light setup I used with a video project I did a while back.