So after two and a half months of waiting 30-40 minutes for every build on the build server, and trying my best to start refactoring the hugeness of our main solution with limited success...

I discover that 2/3 of the build time is caused by the Get Source step deleting and getting EVERY BRANCH IN THE MAIN REPO!!!

This was taking 15-25 minutes. Every. Build.

I changed the build definition to map and cloak the repo correctly, so now the Get Source step takes less than a minute, and the whole build completes in 12-14 minutes...

Yowza! I guess that's a pretty good win to start my two week's vacation on ;-)