Also, what's the current state of the Coda kernel module support for
  non-linux systems? (Do all of solaris, freebsd and netbsd work?)

NetBSD works, but there have been some locking bugs.  In -current, I
think it's ok.  I'm not 100% sure about 4.0_BETA.   3 has the
problems, but the show up fairly rarely, and more often with real
disconection.

I am interested in fixing any NetBSD coda module problems (and can
commit to NetBSD).  It would be cool if you set up a -current system
and ran the arla torture tests; it's on my round tuit list.