Lately it seems like there are less "AA" powered flashlights on the market and lights that run of a single "AA" battery are even more scarce (in comparison to lights using "AAA" and "CR123" batteries).

I don't know if you can find a "AA" light small enough for an altoids tin. If you are looking for a light small enough for an altoids tin, but uses other then coin batteries I would look at Leatherman's Serac-S2 . The Serac S2 uses a single "AAA" and runs at 35 or 5 Lumens.

Like others have mentioned, Fenix makes some nice, relatively inexpensive lights that run on "AA" batteries. Fenix quality and durability isn't quite on the same level as some of the other lights on the market, but I believe you get more then what you pay for with Fenix and I wouldn't have a problem including some of their simpler lights in my kits.

Fenix has a whole series of "AA" powered LED lights.. I would consider Fenix's L1T V2 it is simple and can be found for under $50. I am not sure that it would fit in an Altoid's tin, but I can check when I get home Saturday afternoon.

I personally would use a eGear Pico light and carry a spare battery pack... together with the spare battery it would be smaller and lighter then any "AA" or "AAA" option and have more then enough light for survival tasks... in fact that is exactly what is in all of my small kits.