Hand-powered flashlights

Bought a couple of hand-powered flashlights at a monastery gift shop during my trip.

I kinda figured I'd be able to find something similar on Ebay, but this flashlight is exactly like 1 of the ones that I got! These are a really good idea, unless you want to sneak up on someone!! *laugh* With my little cheap ones (I paid less than $2 USD), you have to constantly be squeezing and releasing to generate the power, which results in a "whirring" sound. Mine have small watch batteries inside (despite saying "no batteries"), but you're not able to charge them. They work with a separate switch, like any normal flashlight would.

Here's a longer list of similar items on Ebay and I also found these nicer models on another site.

Has anyone seen more sophisticated/expensive versions? Opinions?