Depending on your preference for head diameter and switch type, there are quite a few options with Osram W1 LEDs; not quite 900 lumen , but close - and not very power hungry. I think a vendor (flashquark) was just advertising a Mateminco MT35 Mini-S that came with both an 18350 and 18650 tube in the $25 range; possibly cheaper from Ali or BG or elsewhere. My 18350s are Thrunite T1, Catapult Mini, Manker MC13, and Astrolux EA01S; I tend to only carry the EA01S since I can change battery tubes and the T1 for its size.