I used to heads-up the European end of a purchasing consortium for the tyre industry so have a bit of experience.
When you are sitting with a potential supplier trying to negotiate a deal, the buyer's hand is only as strong as the supplier's belief the said volume of orders will be forthcoming.
That was difficult enough to manage with the 6 major tyre companies in Europe, but would be much harder with a bunch of individual potential buyers.
Drive the deal manage to get deals in the same situation, but I think that has taken years; the deals getting better as their track record (in delivering volume) was established.
I think a forum vip type deal may be the best that is actually achievable.
Interesting topic though!