Here's where things stand right now.
I have Nautilus successfully running under Mac OS X 10.8 on a Mac Mini, installed via MacPorts.
I am trying to pull it up on a second screen on a Raspberry Pi running Raspbian. Or really on any other computer.
I have been able to successfully run simple X11 apps like xeyes via X11 forwarding, so I am confident I have forwarding set up correctly.
When I try to run Nautilus via forwarding, I get this long list of errors. I've put it up on pastebin.
I definitely have dbus installed on the Pi, though I don't really know what it is. I'm not sure what's behind these errors or if there's anything I can do about it. Anybody have any thoughts?