I believe LED's are the future of most RE lighting needs.
The Commanda and richhagen links are the best, here are two more that may be useful:
http://www.fieldlines.com/story/2007/1/28/215243/977
claude uses many pics to show how to cluster many small LED's
http://endless-sphere.com/forums/viewtopic.php?f=2&t=2951&st=0&sk=t&sd=a&hilit=l
ed%E2%80%A6
48V bicycles use LED's for headlights.
"I've heard that the only thing that's certain is death and taxes,...but death doesn't get worse every time congress meets" -Will Rogers