I actually did mine per the instructions on the website..  I had two disks in 
the same machine, so I used the ultrix on the one disk to disklabel and dd the
miniroot onto that, and then I could boot the miniroot to label the ultrix 
disk.  Finally, I nfs-mounted a directory on another machine from which I could
grab the tarballs.  This approach wasn't specifically mentioned in the web
docs, but it worked.  The biggest problem I encountered was the whole
labelling shmere at the beginning--I ended up getting the source for the
disklabel program, which happened to include a prototype file for creating
a disklabel.  Then everything was cool.  :)

jdw