Heavy duty flashlight with good built-in charger under 40usd

USB charging port and waterproof will be an issue

Nitecore P25 clone (at about 1/4 the price)
http://www.aliexpress.com/item-img/YUPARD-XM-L2-Flashlight-Torch-USB-charge-5modes-mobile-power-18650-battery-2000Lms-Intelligent-flashlight/1812120970.html

Review here I believe

Samething called the SingFire SF-349 (I own the SF-349 from the group buy)
http://www.gearbest.com/led-flashlights/pp_33496.html

even with cheap sanyo laptop pulls (the red ones I got from Hagg911 for like $.53 a pop [bulk buy]) I was able to use it for over 2~ hours on medium to light my engine bay in my truck while I worked on it…and it never dropped from full power [3 blue leds]