According to Brian Harry (Microsoft Technical Fellow and Program Manager for Team Foundation Server), the next TFS (TFS 11) will be ported to the Azure architecture so TFS could be seen as a cloud service.
just imagine how easy it will be to
- Install TFS (20 sec will be the time needed to activate the service)
- have TFS able to scale to hundreds and thousands of developers
- have TFS available to any developer in the world. Regardless of the countries where your teams are, they will all have access to the same TFS