And if I
wanted to add a SCSI card and/or USB card, will any old
random PC PCI one just work, or do I need something exotic and special
fabricated out of unobtainium?
USB on a Sun box I have no experience with, but ISTR there is some
favored model of Adaptec PCI SCSI card that should just drop in - the
unobtanium part *might* be that you'd have to find a SPARC boot ROM if
you wanted to boot from an attached device. I have only ever booted
from "internal" disks on that variety of hardware.
If you do find one with a SPARC ROM on it, it should be a matter of
stuffing it in a slot and powering on.
Pretty much any Symbios 22801 or compatible should work out of the box.
Peace... Sridhar