Carbon Steel
Yes, the large CV Sod Buster was removed from the Case catalog a while back.
I managed to pick up a couple on eBay a few years ago, and [thread=349841]posted on it here[/thread] when I received my first one.
Pictures from that thread:
There was [thread=352705]another thread[/thread] not long after where I walked through the patina process.
A bit farther down in that thread is this picture . . .
. . . showing the other (untreated) large Case Sod Buster in a "family photo" that includes a Böker carbon steel sodbuster.
The Böker blade is a more ordinary carbon steel, I'm guessing something like 1095. Takes a heck of an edge. Good feel in the hand. Almost exactly the size and weight of the Case.
The Böker line of carbon steel sodbusters is still in production and very reasonably priced.
If you can't find a Case CV on eBay or some similar place, and you really want a carbon steel blade, you might consider the Böker.