Thom,
Forgive me, but are you joking?
3V -- too hard on the equipment
O1 -- completely different heat treat than stainless steels, would require a coating for the general market
INFI -- entirely a Busse exclusive
Nice steels, but not really in Spyderco's realm, right?
Shiden:
3V is CPM-3V, an ultra-tough semi-stainless steel preferred by the likes of Jerry Hossom. Very good for big combat knives to short swords. Hard as hell to work.
O1 is one of the original carbon non-stainless steels. It is oil-quenched to temper, hence "O". I really like knives made with this particular steel, but it stains and rusts if you look at it funny.
INFI is Jerry Busse's patented carbon steel. AFAIK, no one outside of Busse knows how it's made, but some people have said it's a combination of nitrogen impregnation and a serious heat treat/cryo process (I think... don't quote me.) Either way, it's Busse's steel.
-j