We don't have hundreds of millions LoC, but we have a couple of million. We solve the problem you are describing with svn:externals, pulling in the DLL/PDB from

We don't have hundreds of millions LoC, but we have a couple of million. We solve the problem you are describing with svn:externals, pulling in the DLL/PDB from other project/solutions as needed on svn up. I agree it's not as comfy as having everything in one big solution, but being able to count your compile time in seconds as opposed to minutes makes it worthwhile.