They still make the Sporter with an "American Walnut" stock. Now whether that's decent walnut is anybody's guess.
They make this "Altamont" with French walnut as a distributor special for Lipsey's.
Plus TALO has a walnut Mannlicher model in blued and stainless.
I have this "birch Sporter" model with a 22" barrel and have been toying with the idea of finding a take off walnut sporter stock for it.