Interesting. I have a keyring cell phone booster from some catalog company. It takes 4 aaa batteries and has a range of adapters to plug it into cell phones. Ive used it a few times when my battery in my seldom used phone was low. I guess it wouldbe be too hard to add an led light or even go up to aa cells so I can use lithium or even gothe cr123 route.
I saw the one with the 3 led lights in it at lowes today. I do not believe it had the option to charge a cell phone. It seems rather heavy for its size and about the size of a 12 ounce can of cola. The leds were just glowing when I fooled with it. One push make one center led light up, Another push, all three, then another they go off.