both the preon and ld05 claim 23 hours, those are really the only ones I know. I'd probably say go with the preon, I like the coating it has and it is more versatile since you can switch it up as a clicky or twisty and single or double battery mode.
I remember when the UK2AAA eled was the longest running 2AAA at about 20 hours. I replaced the boosted module in an incan UK2AAA with one from a rayovac LED light and now it is direct drive from 2AAA lithiums should run awhile.
I was hoping for stock flashlights not drop ins. I have the Minimag but it is not EDC caliber when there are better choices for 2xAAA. Also I am expecting superb run-time on regular Eneloops not lithiums. I have no need to ever go back to primaries.
The Energizer penlight is probably my longest running 2xAAA. Never really tested it, but it will light up with one battery, so it seems fairly efficient. Not very bright, however.
How about a Peak Eiger #1 with a 2xAAA matterhorn body? It should be about 7lm from an XP-G. I can't find any figures, but it must run for pretty long.
LED Lenser P4 claims 96 hours, max output is 14lm although I believe it's unregulated so output will diminish as battery is discharged.
Haven't tested the runtime scientifically, but I've had a P4 for ~8 months now which I use at work and it's still running at or close to its full output on the original alkalines.
Well the Led Lenser P2 is a 1xAAA that gets 66 hours at 11 lumens, so I'd expect the P4 which is 2xAAA to get at least double that or 132 hours. I guess these lights are only 1 mode models.