Steve, you mention black walnut as root stock, but isn't Claro Walnut more prevalent in your area? Big demand for that amongst gun stock and furniture makers. I heard that years ago, there was little market for the walnut, so the farmers culling the less productive trees every year, ended up burning it. The graft area grain can be very nice as well.
It seems that a lot of wood will come out of a big orchard every year.