The possibilities as you mentioned are limitless, and definitely this can be something, that behaves just the same way as Iron Man's gadget's do, however, a slight difference will be that water vapours provide a surface that can get easily distorted by flow of wind, and might not seem that cool, when compared to a projection on a solid glass surface or some other transparent surface of other material.
But if one can compromise on this thing, then surely it is worthing trying for. Real good mix of technologies.