I like the idea of having the solution per version of Visual Studio. The only problem I can see is this could reduce the speed of availability of fixes / newer versions if the guys have to produce and test various versions of builds.
Personally I would prefer the speed of updates / fixes over multiple versions being made available, and it would take less resource to maintain the downloads area, freeing up more resource for lovely coding! :D
A tough one to call me thinks, I'm sure we all have our own preferences!