DI hooks in the Framework?

Recently we have seen a new side of Microsoft with the community involvement and openness during development of MVC.Net, as well as releasing the source code for ‘viewing’ the BCL. It seems as though it just gets better and better. The Application Framework Core team is looking for your feedback on how the Managed Extensibility Framework (MEF) can provide you with the best extension points in the .Net Framework. Wow, this is exciting news.

On a related note, I heard some rumblings that some future releases (such as v4.0 Asp.Net) will ship with all the unit tests!