It was made by a guy named Jim Powell, who was a long time poster at bimmerforums. It was basically a V1 remote display that was integrated into the rear view mirror, so on the right side of the mirror the display would look transposed in the glass. It was very cool, but he had a real hard time meeting demand. Even when he was doing it, it was very hard to get.
Sample pics for an NSX http://www.nsxprime.com/forums/showthread.php?t=52349&highlight=mirror
Sample pics for an NSX http://www.nsxprime.com/forums/showthread.php?t=52349&highlight=mirror