Shouldn't be too horrible to do.
edit: Done diddly.
Pull any folder you want on to the executable and it will count the folders and files inside and rename the folder to "# OldFolderName". I put the sourcecode rar as well. If you want it for multiple folders at once that can be easily done.
Edit edit: Okay, added functionality to drop multiple folders in at once.
Requires .Net 4.6.1