Adding a little more info. The link I had was to a bid that's ended (on eBay), but this company seems to have these units for all sorts of Lexi. The specs (below) indicated that one can feed any number of video signals into the build-in navigation screen (e.g., video player, TV, back-up camera, etc.).
"CARDEMAND video converter unit that will allow you to add video sources to your factory navigation system. The CARDEMAND converter comes with a vechile specific harness that eliminates the need for cutting or making any kind of modification to your factory setup. The harnesses are made using factory connectors to insure 100% compatibility and reliability. CARDEMAND converter comes with two video inputs one dedicated to a backup camera. The input dedicated to the backup camera has a positive trigger that will allow the back-up camera to be displayed anytime it’s activated with a reverse signal. The unit comes with easy to understand instructions, especially tailored to your specific vechile. Our product is backed with a no questions asked 12 month warranty. This unit is just a converter and will require a DVD player, back up camera, PS2, XBOX, or other sources. The unit is made using the highest quality material and comes in a metal case to prevent any kind video noise. The unit uses a video chip instead of relays like similar models. A relay is a moving part which adds to its unreliability while the chip is a solid state relay that has no moving parts. When using this product please BE AWARE that watching moving images on the screen visible by the driver of the vechile is illegal and could lead to a citation, death, accident, please obey local laws and don’t watch tv while you drive. Below are the specifications on the CARDEMAND unit:"
Features:
Built in color bar
Input auto detection
Digital conversion from input TV signals of NTSC, N4, PAL, PAL M, PAL N, SECAM, to output signals of NTSC-60Hz, PAL-50Hz
Digital line (525 ~ 625 lines) and field (60 ~ 50 field) conversion
6 M bit field memory
Built in 12V DC to DC inverter, ideal for use in car application.
Specifications:
Input Systems: NTSC, N4, PAL, PAL M, PAL N, SECAM
Video Input: 1 Vp-p 75 ohm RCA terminal
RGBS Output: RGB 0.7 Vp-p, SYNC: H+V 0.3 Vp-p 9 pin D terminal
Output TV Systems: NTSC - 60Hz, or PAL 50-Hz (through switch setting on PCB)
Sampling frequency: Y (13.5 MHz), R-Y (6.75 MHz), B-Y (6.75 MHz)
Digital code bit: R (8 bits), G (8 bits), B (8 bits)
Line: 525 ~ 625
Field: 60 ~ 50
Power: DC 12V 300mA power wires