Yup, there's a setup that looks like it costs about $700 but it's intent is to add S-Video inputs and audio inputs into our nav system screen for a dvd player or some other function. But this is the only system I've seen that uses the factory nav system, I can dig up the link if you're interested.. Wait, the link wasn't burried very far, here it is..
http://www.avelectronic.com/NavigationVid-Switcher.htm
http://www.avelectronic.com/NavigationVid-Switcher.htm
