I've just upgraded to the latest version interim drop of the MVC framework and MVC Contrib (which I can't seem to build from source using NAnt...). Everything appeared to be ok, except for one thing: a controller action that uploads a file was now throwing an error:
cannot convert from 'System.Web.HttpPostedFileBase' to 'System.Web.HttpPostedFile'
After a few seconds of confusion I quicky dawned on me that this might be a very good thing. A quick look at the System.Web.Abstractions confirmed my throughts, it now contained abstractions for HttpPostedFile and HttpFileCollection!

Color me happy, the only code I couldn't get covered was Actions that handled file uploads.