Quick FYI:

I am setting up mythtv on a freebsd 8.0 jail on a headless server. After an hour of banging my head against the wall, I was able to, on my ubuntu desktop, get mythtv-setup to work with X11 forwarding over SSH by using ssh mythuser@mythbox -XY mythtv-setup by following
http://lists.freebsd.org/pipermail/freebsd-questions/2006-August/128176.html