Just trying to help out. I don't know about the outputs of the glovebox DVD changer, but I'll say this much, I don't see the point of it outputting to a rear DVD headrest since #1. to which of the two headrests would it output to? A, B or both, and #2 then you'd have to select the output as either from the DVD player in the headrest itself or the glovebox changer and then have to pick one of the 6 movies. Given that you can connect RCA and USB already to those units, this just seems like a slight case of overkill (and I am totally exaggerating here).
On second thought, nope it's not overkill and I have a question, if I install a tv tuner and use a converter to allow it to work after June (or whenever the hell the next 'deadline' will expire) will your setup allow me to use it as a DVR so that I can pause live tv? And please don't forget that I will want to record (on DVD no less) a show that might come on that I like, Matlock or TJ Hooker come to mind. And I presume your DVD burner will have lightscribe functionality, correct?
BTW, I know blu-ray won, but I invested heavily in HD-DVD technology. Will your next gen player be able to read my 3,000 HD-DVD disks?