EDIT: after reading your post more thoroughly I guess you have seen it. Have you tried searching an online catalog for something that meets your requirements?
Espruino is a JavaScript interpreter for low-power Microcontrollers. This site is both a support community for Espruino and a place to share what you are working on.
Have you seen this http://www.espruino.com/Battery ? :)
EDIT: after reading your post more thoroughly I guess you have seen it. Have you tried searching an online catalog for something that meets your requirements?