Probably not exactly what you were thinking of, but I bought a 10,000 mAh battery pack with solar panel the other day specifically for running an Espruino. http://www.amazon.co.uk/gp/product/B00DNX3OQI
Unfortunately, this particular one is stupidly designed with the blue power-level indicator LEDs lit at all times while it supplies power to USB, rather than momentarily when a "test" button is pushed. No idea how well it'll work, but I've got an Espruino running off it at the moment. It's not a particularly fair test considering how little sunlight it's getting right now.
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.
Probably not exactly what you were thinking of, but I bought a 10,000 mAh battery pack with solar panel the other day specifically for running an Espruino. http://www.amazon.co.uk/gp/product/B00DNX3OQI
Unfortunately, this particular one is stupidly designed with the blue power-level indicator LEDs lit at all times while it supplies power to USB, rather than momentarily when a "test" button is pushed. No idea how well it'll work, but I've got an Espruino running off it at the moment. It's not a particularly fair test considering how little sunlight it's getting right now.