My favorite modified flashlights are all incans. I simply don't like LED flashlights. The one that's my pride is the Megalennium 3S 18650... by FiveMega, indeed. Second must be again a FM construction: the M*g 2.5D, taking either 4 pieces 18650 in a 2S/2P configuration or 2 of those chunky 32650s. Add a metal reflector, a glass lens and a Tad Customs PR bulb drawing 1.2 Amps at 7.2V and you have a VERY usable light indeed. Number 3: the Surefire E1e, simply modified with a Lumens Factory 50 Lumen bulb. I now also modified it with a Lumens Factory smooth bezel, as the standard bezel ate its way through many trousers' pockets!