Another model which already exists today is the 'Hollywood model'. People will get together, create a movie and then disband once the movie is done.
In 'the nature of the firm'[0] Donald Coase asked himself why there are businesses with employees at all when an entrepreneur could instead contract the work, a la Hollywood model. The ultimate answer is that the transaction cost of having to go to a market every time you need to get something done outweighs the inefficiencies of having employees. He got the Nobel prize for that.
I got acquainted of those notions trough the book 'Here 'Comes Everybody' [1]. It talks about the way the internet reduce transaction costs and allow new forms of sharing and collaboration that weren't possible before.
[0] http://en.wikipedia.org/wiki/Ronald_Coase#The_Nature_of_the_...