Another idea about the voicebox is to hide it behind a car logo (like the clock/car logos we see here) and when you hit it turns into the voicebox. Make it the same size as the logos and you'll be fine. I also like the visual idea; press it and you'll get a KITT screen look alike. Touch the screen and your main menu comes back.
Is someone willing to do a graphic design of this skin and show us? My car is called KITT

This would be perfect. Integration of the iRunner and Bongo skin will be cool with voicebox in the middle.