I shop at a couple of co-ops, and they're excellent.

Ideally I'd like to chat with a lawyer knowledgeable about co-op formation to create an open template for a version designed to leverage a long term lease from a nonprofit land trust. The structure could be mixed use to include housing; resident owned, appreciation moderated, with support from the trust for affordability.

I've seen a few organizations that might help in a generic way, but lawyers haven't been interested in the 'open' aspect.