After talking with the group there, they seem committed to a path of relying on a certain set of tools that aren't necessarily up to the task at the scale they want to run their service at. It would be like AOL building their instant messaging platform on top of Visual Basic, and insisting that no one write anything outside of that. I don't think AIM would have scaled to 600M users that way.
So my small tidbit for today: ssh -v -X hostname is the way to find those hidden problems with an install that you aren't going to see any other way. -v gives you lots of great arcane information, which combined with google reveals many things. Oh, and the answer was, sshd won't forward X11 without xauth installed.