> Has anyone else seen problems with Ultrix binaries?

Yes.  I've seen similar behaviour.  I suspect it may actually have to
do with VM problems rather than an actual binary incompatibility, but
I'm not sure about that.   Ultrix Mosaic definitely hangs my machine
from time to time.

> I still don't have a NetBSD native groff, emacs, or xterm!

NetBSD/pmax binaries for all of those programs are available on
ftp.netbsd.org!   (Not that I want to discourage you from looking into
the Ultrix binary compatibility problem, mind you!)

			       _MelloN_