I sometimes use my BLF X5 (identical to Astrolux S3) which is capable of emitting 1.400lm with an Enerciq Tensai TN14500HP battery. This flashlight has however no
stepless ramping but maybe with another driver from Lexel oder TA it might be feasable. Make sure you buy the right high drain battery and keep in mind that fun will last for no more than a couple of minutes with such a small battery capacity.