I recently got a new bicycle, so I was interested to run across iBikeConsole, a new iPod nano-focused accessory designed for cyclists. It combines two wireless remote controls with a central weather-resistant iPod nano case. The remote controls mount inside the hand grips and can be used while wearing gloves, while the central case also includes a cycle computer with distance and speed functions displayed on the nano's screen. The whole thing is powered by the nano's battery, the it will store data even after the nano is removed.
It's designed to work with 1st, 2nd, and 3rd generation nanos. I contacted the manufacturer to check on compatibility with the just announced 4th gen nano, and they say that they have yet to get one and so cannot confirm compatibility. We'll update this post when more information is available.
iBikeConsole is available for $76.00.