I have been using the P-T path program of Moynihan and Pattison (2013, JMG 31 525-548) for a few years and have a version for Windows 7 that I have been giving to anyone who asks. If you would also like to try the program, just send me an email. I have made several modifications to suit my own needs, but the search function is the same as the original, and there are some additional features that make the process a little easier, faster, and more transparent. I'm sure a Mac/Unix version could be made with only a couple of modifications.
Eric