Logitech‘s Wireless Solar Keyboard is wireless and solar powered. It will stay charged up for up to 3 months in a dark room and can glean power from indoor lighting. The keyboard itself is just 1/3-inch thick and includes Logitech’s unifying receiver. To measure battery life, their is a Windows 7-compatible solar app.
Logitech’s Wireless Solar Keyboard K750 will ship November 15th. You can preorder it for $79.99.