Huh, putting projectors into a pair of glasses and projecting on a retroreflective surface ... now there's an idea which makes me feel stupid for not thinking of it :/ Still a bit expensive to play board games with for most people ... maybe the military boardgame crowd will adopt it? They aren't afraid of spending tons of money.
http://hackaday.com/2013/05/31/jeri-spills-the-beans-on-her-ar-glasses
PS. I just realized that with normal microprojectors this won't work all that well at short distances (such as virtual board games) since you get into trouble with depth of focus ... you really need projectors which are always in focus such as with scanned&modulated laser ... but I don't think they can do that for 200$, cheap scanned laser microprojectors have been 6 months out for half a decade.
http://hackaday.com/2013/05/31/jeri-spills-the-beans-on-her-ar-glasses
PS. I just realized that with normal microprojectors this won't work all that well at short distances (such as virtual board games) since you get into trouble with depth of focus ... you really need projectors which are always in focus such as with scanned&modulated laser ... but I don't think they can do that for 200$, cheap scanned laser microprojectors have been 6 months out for half a decade.