CEGeek, those CE car radios are hybrids.
The radios have separate circuit boards in them. One is for your standard ARM based CE handheld, the other is for the video connections.
All the CE part does is act like a menu program and control the GPS. On the CE side you have the standard group of basic image viewers, AVI/MPeg players, ebook reader, etc. Most of them run the CE version of iGo 8 GPS software. The FM radio is also CE controlled. Funny that most of these don't have AM radios in them. Also the one I installed had CE bluetooth as well.
The non-CE side is the DVD player, which on some is actually a DVD recorder as well. I noticed on the one I played with that it had a jack on the back side for AV in, and you could record the image to a memory card, hence you could use it for a backup camera, or use it for a trip recorder.
But I guess what I am saying is the DVD rendering is not part of the CE coding.