iSkin Claro for 30GB iPod Video
While this case is very nice in concept and definitely would work to protect the ipod, you cannot use it with any FM modulator in the car without taking the case off.  The only option around this is to hardwire a modulator into the car, but then the ipod won't charge, which seems silly to me.  All in all, not a good product since you would have to take it out of the case to do anything with it besides sync it with your computer.