The dev units have already been demoed at E3 and now at Quakecon. According to the interview Palmer gave to EG recently, the prototype units will actually look quite close to the proposed commercial unit (externally that is). The main difference being the panel used in the dev units being relatively low resolution (1280 x 800). That panel is likely to change before the commercial versions ship.
Phattso - what exists today?
Apart from in theory, I mean.
Dev units are already with various top level devs, Valve, Epic the Unity engine guys etc. and feedback on the whole has been overwhelmingly positive. What's more is, although the Kickstarter dev units are shipping with very little in the way of profit for Oculus, it demonstrates how cost effective the approach is for mass production (much less than £200 for a full, working unit).
According to Carmack, the focus now is on upping the panel resolution and lowering the latency of the headtracking sensors as well as tweaking the optics and providing adjustable focus on the optics (currently this is not available).
As carmack puts it, the tech exists today to do all of the above, the blocker ATM is both developer backing and panel manufacturers producing cheap, high resolution panels - ideally OLED (it's currently an LCD panel).
In all honesty, this isn't a pipe dream any more. Of course, making a commercial prospect is another matter. But, I get a good feeling about it. Momentum seems immense already and this is before anyone has their hands on the kit.
Edited by silentbob at 10:09:12 06-08-2012