Not a bad idea, really. A "collective of shooters" would certainly help those looking to run a few rolls of film through their cameras every now and then, and would keep costs reasonable. Despite the professional intent of this forum and others, I suspect a significant number of posters and regular visitors do not work in the film business, but nonetheless have a deep interest in the subject. I certainly don't earn any money shooting 16mm film, nor do I expect to in the future.
Cinematography is "just" a creative outlet for me, one I would like to pursue on a deeper level, but find myself limited not necessarily by equipment and money (although those are certainly factors) but also by lack of real world contacts with whom I might collaborate (sharing time, talent, equipment, and cost) on a singular project. Personally, I'm not interested in shooting vacation film or family holidays- that's what video is for. I want to make narrative films, but: a) Have limited equipment; B) Don't know many people who share my passion for filmmaking; c) Am a working professional who doesn't have the time to visit local film schools in hopes of drumming up contacts, and frankly am not terribly interested in working with students anyway.
My point being, given the apparently vast number of visitors to sites such as this one, and the rate at which older, decidedly non-professional cameras trade hands on eBay, I can only assume that there are a hefty number of "armchair" cinematographers and camera nuts out there, a percentage of whom would probably like to participate in some actual production work, if only for the sheer joy of it. One fellow might own a decent camera, while another has a good set of lights and a sister who likes to act. A third person comes along and can contribute writing skills and a tripod. Sooner or later, you've taken a bunch of people who would otherwise be shooting 100' rolls of their trip to Disneyland and turned them into a production company with some potential. They probably won't be making the next Sundance surprise hit, and they surely won't be turning a profit, but they will be having fun, and that's what counts in the end. If someone provided a place (online, ironically) for these folks to meet and form those intial connections, I have little doubt that it would ultimately result in the formation of production companies that would not have existed otherwise, film stock that would not have been sold, cameras that would have remained in closets, actors undiscovered, scripts unwritten, films not made.
By nature, filmmaking requires collaboration. I suppose you could lock the camera off, flip the run switch and jump in front of it to act, but come on- that's only going to satisfy you for so long, and trust me, you feel pretty silly doing it :) .