If you have a decent monitor, the sync on green should not be an issue. Older
Macs and many workstations (SGI, all 3w3) run sync-on-green. If you do a
search on "connecting PC monitors to SGIs"
or similar it should tell you known monitors that work SOG. In any case, it's
probably much cheaper to find a used monitor that supports SOG than to buy a
box. Sony's monitors are a good bet (have 2, one OEMed by Radius, one by IBM,
both work Sync-On-Green.
-Scott Quinn