I'm thinking two is a good place to start. I'm envisioning a whole network of hackerspaces. Actually, we wouldn't have to limit to hackers.

I think arts groups like The Field could also benefit from something like this.

http://www.thefield.org/

Probably not quite what you mean (focused more on tinkering than startups), but I can't not link to http://hackerspaces.org when I read "a whole network of hackerspaces".