It's quite helpful that TM's project files are xml (plists, i believe).  I recently had a need to update the paths to a whole bunch of resources in a project I'd setup.  It was a fairly easy find/replace operation, but I had to perform it in TextEdit because I couldn't get TM to open the file as a text file instead of as a project.  I suppose I could have resorted to some form of file renaming shenanigans, but I'm wondering if there is another way.  Does anybody know how to do this without resorting to file extension trickery?