built one out of a 7 dollar plastic flashlight. hogged out the ridges on the inside (that hold the batteries) so i could use 3 surefire 3 volt batteries. bought a 9v surefire krypton bulb, and viola, 16 bucks and it's 85% as bright as a surefire, and i don't care if i lose it, break it, chuck it at a beaver, whatever.
http://www.youtube.com/user/kipkay#p.../2/mnkjvEdeIlc
police flashlight hack is the video. fun project to do with your kids too.