Can anyone think of a way to mount the empeg in the trunk and have it send video/audio to a nav system?

Until the remote display becomes a reality, the only simple method anyone has been able to come up with is to mount a cheap CCD camera aimed at the empeg's front panel, and use an infrared repeater to control it remotely.

This assumes that the CCD camera has a composite-video output, and that your LCD screen has a composite-video aux input.