Thanks. I find a lot of the Plan 9 stuff very fascinating, and I often think about what it would take to port some of the functionality to OSX.
I find it interesting that you mentioned the window management as being one of the big selling points. I have been working on a tiling window manager for OSX, and might try adding a mode like that. It would mean splitting my emacs into frames, which could be weird. Probably worth messing around with, though.
Also, I have several emacsclient based commands to do things like the plumber/acme, but is a pretty poor attempt at reimplementation.
I don't actually take the Plan9Ports thing as far as I could (I work on Linux, mostly, often with a drawterm connection open to our Plan 9 server). I run a plumber, and Acme, but I don't run rio (the window manager) or 9term (the xterm replacement), which means I'm going to miss out on some of the plumbing stuff. Mostly I just run the plumber so I can say "B <filename>" at a shell to have it pop up in my Acme.