The best option I've found for lights is from this company.
http://www.lifegear.com/glow-sticks-1/glow-stick
You can find them at a large number of stores, including some hardware stores. To make the flashlight mode be the colored light, you just unscrew the top from the glow stick part, slide the electronics out, and then put them back in the opposite way. The button will line back up properly if you do this.
Also, free batteries for life.