SQL Server Developer Edition—Downscale Emulation

IMHO, I think that SQL Server Developer Edition should have a “switch” to permit developers (ideally on a connection-by-connection basis) to “select” which version of SQL Server is being executed. As most of you know the difference between the versions is all done with mirrors as the bits are the same for the most part. I can’t see that it would be that hard to expose that selection switch so a developer could test his application and the server-side executables on the version of SQL Server he or she is targeting.