So, as the title reads, I have a VS2010 solution with ~50 projects in it right now. If I make a change to a \"top level\" project that nothing references then VS still rebui
For this category of build problems setting MSBuild output verbosity to 'diagnostic' is indeed a necessary first step. Most of the time the stated reason for the re-builds would be enough to act upon, BUT occasionally MSBuild would erroneously claim that some files are modified and need to be copied.
If that is the case, you'd need to either disable NTFS tunneling or duplicate your output folder to a new location. Here it is in more words.