Sometimes searching the Internet for associated parts in home brew LED bicycle lights can help narrow the field. For example: searching for "buckpuck" brought up more homebrew systems than a search for LED lights that could include flashlights and other lights not associated with bicycles.

Some of the thirty-two examples from a WebFerret search under "buckpuck":

http://www.mouldy.org/projects/High-Power-LED-MTB-Light
http://buttersideup.com/DIYcycleLEDs
http://www.outsider.plus.com/bikelights.html
http://www.instructables.com/id/E2K9BN5EDKEUBYRD9V/