Nightstar makes the only “real” shakelight, I own one of those and it is truly like something from a sci-fi movie, it actually works and would be a durable, permanent flashlight for a mad-max world, for instance the magnet doesn’t hit buffers when it is shaken, it runs into two other repulsing magnetic fields, so there is no hitting anything, which could wear, also the capacitor is high quality, Nightstar is very conservative in their description, too conservative, the light produces much better than their modest description.
They also make crank lights which are probably very good.
http://www.appliedinnotech.com/products/shake-flashlights/nightstar4.php
People should remember that they can always bring in those solar powered garden lights, and also, most of those have AA batteries in them, so some of the batteries can be robbed for flashlights, and put back in for charging during the daytime.