Polyglot, I must admit that having a shared facility was something that I had in mind a long time ago, but the reality of it, is as you have described. Will it get used? Then there is the cost (Surely the only way to do it cheaply would be to set it up in either Elizabeth or Hackham.....and then I am sure you would get plenty of other attention for other chemical uses...). Who never knows, but I think that this would beyond the scope of such a group.
Fleath, I think you have hit the nail on the head. I am sure that as a collective, the purchase of supplies would be a high priority, especially for staples such as Rapid Fix, non specialised developers, film, ect. I also am more looking at the social aspect and shared knowledge. I would imagine that meetings would be more of a monthly, or bi-monthly period. I would also suggest that locations would need to be as central to the Adelaide metro area as possible.
Keep the ideas coming