You guys have me looking for this stuff now as well! I have made my own unit out the the carconverters RGB converter and have it configured now with an in-cabin rear seat camera with IR leds (So I can see the kids at night - has been great for letting me seeing if 18 m/o junior has gone to sleep on trips to/from babysitter at night) and reverse camera that is triggered by the reverse light.
I came across this unit too:
http://cgi.ebay.com.au/USB-2-0-HDD-H...QQcmdZViewItem
It has NTSC and even does RGB component out - so theoretically you wouldn't even need the ASL conversion, you could hook it straight up to the NTSC RGB input in just above the tissue box.
I might even be able to put this into the ' RGB pass through' input on my converter which is supposed to allow for pass-through of the Sat-NAV connection.
Cool!
Lukeyson