The way I have setup TFS for our team is to have branches per environment. Contained within this project is multiple applications and libraries that logically group together.
$/TfsProjectA/Development/Source/WebApps/WebApplicationA $/TfsProjectA/Development/Source/WebApps/WebApplicationB $/TfsProjectA/Development/Source/Libraries/LibraryA $/TfsProjectA/Development/Source/Libraries/LibraryB
$/TfsProjectA/Staging/Source/WebApps/WebApplicationA $/TfsProjectA/Staging/Source/WebApps/WebApplicationB $/TfsProjectA/Staging/Source/Libraries/LibraryA $/TfsProjectA/Staging/Source/Libraries/LibraryB
(Staging is a branch of Development)
Now to merge all changes to one whole application and all it's dependant libraries to a different branch is quite time consuming and painful.
I have already written a PowerShell script using PsTFS that can merge by solution but it is a bit clunky and sometimes a little dangerous due to the limitations of PsTFS; I like live on the edge! ;). I'm thinking of polishing it up and turning it into a full app or plug-in to VS, but wanted find out if anyone knows if this has already been done elsewhere and I can't find it, or is a feature of TFS2010?