Yes, you can add your Project XMLs to the Template folder...
This folder can be modified and your Templates removed as the system is updated with future releases. You will need to mind the changes as you perform those upgrades. You will most likely have to replace them after the upgrade completes.
The other option is to create a "Template" folder and have them just pick/choose from that folder (Read only) then just copy it into their working folder for tweaking/modifications.