All the way back in 2009 I wrote a little console application that assisted with renaming a Visual Studio project and/or namespace. It was handy in that it took into consideration the solution being under source control with TFS. Over the years I have been using TF source control less and Git more. On the odd occasion I have also used this script for solutions that are not bound in source control.
I have refactored the script to take out the TF integration, remove the logging that was just causing a whole lot of white noise and to add in a few more out of the box exclusions for directories to skip in the process.