What would be interesting would be a brewpub what is set up, where a homebrewer could come in, brew their own recipe, and be served and sold at the brewery.
(I'm making this up as I go along, with the help of a couple high test beers, so I don;t know anything about the legality of this...)
So the (home)brewer pays for the ingredients, possibly working with the brewpub to source them, and the profits would be split between the brewer and pub?
so, using the recipe for a tripel I'm ordering up, cost is about $40, I'd get about that many (US) pints out of 5 gallons. So if the pub was to sell that beer at $6 a pint, that's $5 profit, split, even 50/50, that's $100 to the pub. Scaling that up to even a 2 barrel system increases that, of course. I'd have to look at costs and such to see what would pay - even say $2 a pint to the brewer, so cost + a buck profit would result in a big profit for the pub. They may have their own house beers as well, aside from guest brewers.
Obviously there's costs to the pub - staff, insurance, the costs of the licenses and such, cost of the space, equipment, etc etc etc.