I've got a few 5000/120's booting diskless now, thanks to Herb Peyerl
for pointing out the missing -alldirs switch in my server's exports
file.   The point of this exercise was to prove to myself that a diskless
installation process would probably be easier than the current
process.  

If there's any interest in supporting diskless installs, I'll be happy
to write up a diskless installation guide for NetBSD/pmax.  What's the
consensus?

Drew