S: there are saeveral at DX that can use NiMHs that are quite nice as well, search for this item below there (their site is down for maintenance now)

Uniquefire S10 Cree R2-WC 6-Mode 220-Lumen Memory LED Flashlight - Black (1*AA/1*14500) 0
Item# 30986

There are some advantages for AA driven, I think the issue for many is that it's easier or safer to use 1 single cell for these lights since if you carry a backup battery, then you know the backup is charged. If only having the lamp, then maybe the battery in it is near death. Same for 2 cells. But once going with 1 cell, it's much mroe possible to get a brightly driven light with an 18650 since it's above the forward voltage of the LED and doesnt have the same efficiency issues as a lower voltage cell will.

Once making this small investment in 18650s ($8 for 2 batteries, $8 for charger) it's hard to go back. You can also harvest the 18650s from old laptop batteries.

The fact of the matter is that a $15 18650 flashlight is equivalent in brightness and runtime to many lights still costing over $100 and you won't outrun it except over 45-50 km/h.