Having dug into the internals of the current Perforce plugin a bit, I wasn't too surprised when it turned out to not work at all under MacOS X (new 3.0 support has been released). That said, I'd love to see this working.
Currently it NPE's, and debugging plugins is pretty awkward so without putting some work into it I'm not sure exactly what's failing. The good thing is that it NPE's in the "Test", so this probably isn't entirely hard to replicate.
I guess I'm wondering at this point if anyone is working on getting Perforce plugin support working under OS X? I'm as lazy as the next engineer, so if someone else is doing this work then I'm happy to wait. ;) That said, I am fairly motivated to get it working, and obviously I have an OS X machine to work with.
I'll be doing the obvious stuff to see if I can make it work tonight, and will report back if I find it's pretty simple.