I dont know if anyone has tried these but they are very bright

http://www.lumiledsfuture.com/products/family.cfm?familyId=7

I bought some of the red ones for my thesis project and they are very bright. Much brighter than any other led and for their size brighter than incandescents ive seen. They are also used in the ultrabright LED flashlights. They are designed to run on up to 1 amp which may give an idea compared to the milliamps that most LED's draw. Im not sure if they are ideally suited for gauge lighting but they may be worth a look.