I just had to move a large project to a new build and didn't want to download all 40 gigs again from my SVN server. I recently updated to version tortoiseSVN 1.7 and noticed that it took all the .svn hooey and put it into one folder at the root of my install. This made me wonder what would happen if I just moved that folder to the root of my new, stock install of UDK and update. BAM! It worked! It takes a while to copy the working copy back out of the .svn cache but it's WAY faster than a checkout and way easier than doing it by hand.
- Copy the .svn folder from your old build
- Paste the .svn into the new, fresh build
- SVN>Update the new build
- Drink Coffee