A longtime HOS member with family in the Midwest came home to Oregon with "fists fulls" of Native Persimmon trees to use as rootstock. He said they grown so thick and wild in many areas that he simply walked along pulling up all he wanted, leaving hundreds still too close to each other to prosper. They worked excellent for excepting the grafts of Oriental "Highbreds."
I've grafted Persimmons myself, they're very late to leaf out and may appear not to have "taken," but give them months before giving up. Each of mine eventually grew.
Do you have any members heading to, or living in the Midwest? Perhaps a "like Organization" in those states might pluck & send you some? Good luck!