From the human wave school of lighting philosophy, I got a couple dozen of these $1.50 lights from countycomm, in orange with the clip. They use 2032 (or 2016? can't remember) batts. Requires a small phillips screwdriver to change, but if you have a dozen, you're ok. they have a manual slide switch, not a squeeze switch. I stick several of them inside various bags for bag illumination.

http://www.countycomm.com/ARES%20SOLED.htm

Not that these take the place of a good, rugged light, but great for supplements.