I like the Oveready TorchLab Moddoolar H3C with triple XPG2, and with a 50mm battery tube, and the Shorty ZeroRez tailcap.
It's about 4.25" long, and can accept 2 x 18350 batteries for a max output on high of 1600 lumens. Relatively short run time, though.
Or, if you want to accept a lower output, you can put 1 x 18650 in it, and it will give 1100 lumens for a longer time.
If you prefer Hi-CRI color rendition, you can choose the H3N with triple Nichia 219 for 1100 lumens with 2x18350, or 780 lumens on 1 x 18650 for longer run time.
All very easily fitting into your pocket, on its own pocket clip. Awesome machine work, too.