These sound pretty neat for a disaster scenario.

What factors should be considered when deciding between AM and FM capability? There are certainly a lot more FM stations where I live, but I believe AM signals travel farther into unpopulated areas. How did you decide?

By the way, if you want larger battery capability, I saw a tiny FM radio at WalMart with plug-in ear bud headphones that took one or two AAA batteries and had digital scanning tuning. It was only $1, but I don't think it is a normally stocked item. It would probably fit in an Altoids tin, but would take up most of the space, so not as compact as what you describe.