Wait a couple of weeks and Gene Malkoff should have some of his drop-ins available. Just pull the old light bulb out, put his new thing in and stand back and admire a wonderful upgrade (without any hassle) to the maglite.
If you don't want to wait, look around in the Homemade and Custom Flashlights forum and there are a couple of tutorials on how to easily mod your mag with a heatsink, resistor (control board or micropuck too), emitter...some quick soldering and you will have a nice mod done by yourself!!
I have done both and I need a couple more mod experiences to even match what Gene has done. His drop-in may be considered expensive, but you are getting close to the price with all the stuff you need to buy to do the mod. In less you like having fun making stuff, the malkoff drop-in is a very easy (and foolproof) way to go!!
Bob E.