as of OS 3.0 - only way I know is to use an text editor and copy details of core.pyr from one project to another. its not user friendly, and easy to screw up.
so id not advocate unless your feeling brave, and you think its going to save you a lot of work. (which is unlikely, as most of the work is probably in the midi files which are easy to copy)
i kind of touched on core.pyr hacking here