Hello James,

  JET> The only "internal scsi" connector I know of in a
     > 3/60 is the P4 connector which is used for the color
     > monitors.

This picture on Craig Dewick's Web site of a 3/60 mainboard
shows a bare area (at top, left) where a 3.5" hard disk
could be screwed to the board.  IIRC there are pads for a 50
pin IDC header between that and the P4 connector...

 http://lios.apana.org.au/~cdewick/data/sunpix/sun360-2.jpg

    ...anyone comfortable soldering multi-layer logic boards
could fit a connector there.  I'm guessing there are
terminator resistor packs nearby that would be removed too.

I doubt the P4 uses SCSI, although I've heard of SCSI 'video
cards' being used with ancient Macs that didn't have an
expansion slot. I've also seen a small box that connected to
a disk drive (and optionally a host system) on the SCSI side
and used a hardware MPEG decoder chip to play (composite
PAL) video out of a phono/RCA connector.

  JET> One inexpensive way to get a high number of drives
     > onto your machine is to get a used AT or ATX case
     > and have an internal cable...

I've done this with an old PC case that had an AT power
supply.  Persuading an ATX PSU to power up with no mainboard
attached might require a hardware modification.  I used one
of these...

http://www.cyberguys.com/templates/searchdetail.asp?T1=131+1750

  ...external HD50F to internal IDC50M adaptors for the 'box
of delights' that I built, which enabled me to use an
ordinary (inexpensive) 50-way ribbon cable inside the box. I
connect it to a host computer using a 91cm (3') HD50M-HD50M
cable.

- Andy Ball