If working space is not going to make money, but is useful to you, perhaps you should consider some type of co-operative arrangement.
If it were structured as a joint ownership, and all customers had to be members, you might also avoid certain licensing requirements aimed at a place open to the public. Think along the lines of the Gentlemen's Clubs of Victorian London, or a Freemason's lodge.
If I were to join, I'd like for a back room or upstairs attic or something to be designated the "Diogenes Club" were no talking or phone usage was allowed.
That's coworking: http://en.wikipedia.org/wiki/Coworking
San Francisco coworking spaces include Citizen Space in SOMA near South Park: http://citizenspace.us/
And the Hat Factory in Potrero: http://hatfactory.net/
But these places have their limitations, and everyone thinks they can do one better. In fact, Digg founder Kevin Rose likes to say that when he cashes out, he'll start a teashop, but he once fantasized to me about starting a tech artists collective. I even encouraged him to try it, but I have a feeling it'll never happen.
Because to be honest, running a co-working space for people too cheap to find their own offices, going full-service without the high margins of a high-volume walk-in cafe, dealing with customers with serious entitlement issues, is not nearly as fun as all the other businesses a talented tech professional could start in SF or Silicon Valley.