> Hypothetically speaking, I don't want IRIX. So could I just buy a
> null-modem serial cable, attach it to another computer of mine with
> some "serial console software" and use the O2 as a command-line only
> BSD machine?

yes. i've done this with an Indy, makes a nice server, especially in a rack.

> And on another note, I realize this is the wrong mailling list, but
> does anyone know about Debian or Gentoo for the MIPS arch, would it
> support a graphical UI?

the underlying problem is availability of drivers for the proprietary sgi
graphics hardware; if these existed in debian/gentoo, someone would most
likely port them to *bsd (and vice-versa -- granted, i'm ignoring the
potential license issues for simplicity's sake).

so far, only the Indigo gr2 and Indy newport hardware is supported. so
if you want a gui, search EBay for a downgrade :)