You might be right, I just took a quick look on Ebay and found some interesting stuff.
I'll have to do a serious search this evening..
This seems like something to try. I can't see how it has such a large voltage range..
White 8-LED Super Bright Car Light Bulb 3 Watt DC 8-30V - eBay (item 190459203966 end time Nov-20-10 07:52:49 PST)