If you were going to attempt to collaborate a group buy on Gen III devices, the place you would want to go is AR15.com and make a mention of it in their NV forum which is under the Armory forum.
Night vision sales churn out of that place, because there are a lot of people posting there who are using them vigorously for hunting or the work they do, rather than maybe just star gazing for fun. A lot of the hard core NV addicts are there.
If you got a group buy going, I suspect the majority would opt for the best tubes available, which is ITT thin-filmed Pinnacle tubes (Gen III of course). Most debate on this subject has yielded that you are much better off by starting with a Gen III, and if you can't afford it, simply don't own nightvision at all. The sad truth is that the Gen I and Gen II units just can't perform in dark conditions, and you are better off saving your money than giving in to one of those inferior units which will give you even less than what you payed for.
Assume that everyone settles on the ITT PVS-14 Pinnacle monocular for a group buy. The cheapest net price I can find one at now is $3,800. How many people do you feel would be immediately ready to pay $3,500-3,800 for a new monocular? I think very few people would be willing to participate, and the people willing to buy also probably have enough extra cash that they can simply order the unit now without worrying about the group buy in the first place.
If you want a cheap route, the cheapest way would be to build your own set. Gather the parts, and then complete the build with a new Litton ITT tube, and send it to a technician who will assemble it and seal the unit with pressurized nitrogen. Watch places like ebay and Gunbroker for parts.
True dual-tube binoculars are the most expensive, but give the best picture quality, since they have 1 image tube intensifier per eye. The PVS-7 head unit only has 1 image tube total, and the available light from that tube must be split to feed an image to both eyes. Since it's the same image both eyes see, there is no depth perception, and the scene will not be as bright and clear as having the light pumped from two unique sources.
A good monocular is the best way to start, specifically an ITT PVS-14 if you may someday possibly attach a second unit to make a pair of binoculars such as I did. If not, there are other great monocs out there, with same image tube quality, but smaller and lighter exterior designs that carry easier on a headmount.
) ..... i was working in the room where the controller and screen was, and seen the "camera" part only when they placed it in the test room (and also if i was curious, i tought it was not the case to ask "sorry, can i dismantle it ?" ..... 
