I think I know what you want snowfox...because I want the same thing. I want a hud built into my glasses that feeds me real time information..a la robo cop.
Although I'm sure someone is doing research on this...as it is just too cool not to invent...right now current technology seriously limits a DIY answer.
However..if I had to "Macgyver" one with available parts to me it would go like this:
I would start with a base of a construction hard hat..it has a nice inner support frame...and attach a 3 point chinstrap for maximum stablity..cause this sucker is going to be heavy. A football helmet would also work nicely.
The only projectors that are currently available to me at my computer recycling job look like this:
You would have to mount it to the top of the helmet like a shark fin in order to keep the balance and position the lens correctly.
Extending outward from the top of the helmet would be a couple of aluminum supports that would hold a mirror that would reflect the image downward onto a small piece of plexiglass positioned a few inches from your face.
Since the projector uses only wall current..and a lot of it...you would need a large battery and inverter in a backpack to run the thing...plus a laptop to run the software.
Hey...it might work...be heavy as hell and unwieldy. but it might work...and you did say low tech.