Didn't they try the HUD thing before in the early 90's. I think they scraped it because of a saftey issue. Something about the screen comming loose and bouncing around in the helmet. Anyway its a really cool idea, it makes the F1 cockpit look even more like the cockpit of a Fighter Jet.
I would think that would be dangerous, I dont know how many of you guys race cars here but thats the last thing I would want in my helemet. I think it would get in the way in close situations.