OK, there is a way to save your item sets. I seem to remember a troubleshooting option that shows you how to backup your hard drive data so you can do a reset on LoL and retain your data to replace the reset version.
It's in the troubleshooting section of the patcher program, and is also in the troubleshooting section of the boards.
It shows how to copy certain files before resetting the game.
save these files each time to separate folders in case something should happen.
I back mine up at least once a week.
Just in case... :)
Hope this helps!