[ Note on the SCSI problems...  I know that the ncrscsi driver has
  problems.  I'm 99+% sure that they're mac68k-specific and I also don't
  have any good way to try and reproduce the problems right now, or the
  time to work on it if I could.  Please work on it if you can...
  (that's not a specific "you"--it means anyone who reads this). ]

> This has probably been mentioned before, but in the file.mac68k there
> are two "Options" for SCSI. Do we enable/disable one or the other simply
> my commenting out the appropriate 3 lines and rebuilding the kernel?

Nope.  Specify either:
sbc0		at obio? flags 0x1	# MI NCR 5380 SCSI Bus Controller

or

ncrscsi0	at obio?		# SCSI NCR 5380

in your kernel configuration file.
Those examples are from SPOT and PUMA.

-allen

-- 
              Allen Briggs - end killing - briggs@macbsd.com