I saw this rear-view mirror, and I though that it would be a great way to get an integrated hands-free cell adapter into a car, especially since there are any head-units that have integrated Bluetooth, and integrated iPod and satellite radio controls.
The ModooFree BT does give you a integrated hands-free cell phone adapter, that could look pretty good installed. One thing that I don't like about this is that it uses the cigarette lighter. I would be more interested in this if I could hard wire it behind my dash.
I may get this, and modify the wire myself, since this can be found for about $149. Here is the Froogle search for it.