Obvious thoughts: you need to be able to track the head (and, probably, the eyes) in real time, to adjust the positioning of the objects on the display. Not having a glow outside the vehicle is likely to be Too Damn Hard. Powering the thin film without introducing visible (even if faint) lines is highly likely to be problematic.
I very much doubt the underlying technology - especially on the thin film; everything else (cameras, eye tracking, etc) is probably close - is anywhere near ready. It'd be cool, though, I agree.
The eye/head tracking was just assumed as it's already current tech or, if not, can probably be quickly hacked into a Kinect combined with the face/eye-recognition software of current digicams. The no external glow criteria was always going to be the hard one. As for the wires, the issue is going to be the density of them. Too many and you've set up a diffraction grating and it's all rainbows all of the time for the driver. Not good. I'm thinking there must be some way to transparently dope this membrane ala PCB traces so that it acts like a PCB but without obvious wires. Depending on dopant capabilities and the transparency of multi-level membranes it may be possible to have a power level that covers the entire sheet with doped vias where necessary. If it's really good it could take enough power to act as a defroster/defogger, but that would really be gilding the lily.
My greater point is that there has to be some way for tech to compensate for the declining night vision of us old farts. I can avoid it if I can see it, yet but one month from 50 I already sense that I'm not seeing anywhere close to as much as I used to see at night. Given that the day job has me in the car for 25K/30K miles per year just in Vermont and that I'm at least 15 years from any potential retirement, I really want a tech fix to my problem.
Oh, and dreaming about tech that's "near ready" misses the entire point about tech dreaming.
When I win the MegaMillions on Friday I'll throw a few millions at a VC startup just to get this off the ground.
The GM HUD was a small (about 4"x4" IIRC) box reflected onto the windshield that was nothing more than a repeater for the speedo/tach. I'm thinking much larger. It was also '80s tech.
Never ask a woman who is eating ice cream straight from the carton how she's doing.