I think there are some initiatives under the creative-commons tag that is also getting people to collaborate and contribute for the community, although most of it has been spear-headed by artists rather than writers (of the more non-fictional genres). But that's not to say that a similar model wouldn't work in getting a body of work written and published and I think perhaps the proof-of-concept needs to be how different people can co-author and publish something in a similar way to wikipedia (if that's an appropriate model for what you are thinking of)?