I am so enamored of my solar-powered, wireless keyboard from Logitech that I had to mention a new product that I just heard about from Taiwanese technology company Genius: a battery-free mouse called the DX-ECO BlueEye Mouse.
According to the product specification sheet, the mouse uses a rechargeable gold capacitor instead of a battery. The capacitor charges fully via a microUSB cord in about three minutes. The Genius BlueEye DX-ECO product literature doesn't say how long the capacitor will hold a charge, but it can be recharged up to 100,000 times.
The device uses 2.4 Ghz wireless communications technology (which means you have to use a Pico receiver, which will require a USB slot). It can communicate up almost 50 feet away. There is not shortage of buttons and features, including a scroll button, a button for adjusting DPI settings, and even a button for clicking back and forth between pages (previous and next). The products supports Windows 7, Vista and XP and works with Macintosh OSX 10.4 or later, according to the specs.
The suggested retail price on the DX-ECO is $39.99. I haven't managed to find the mouse for sale at any of the usual retail suspects, although the company appears to have a relationship with many of them.