I wouldn't rule out South East Kansas as well!! Maybe around the Pittsburg or Ft. Scott area. Also maybe try around Nevada, MO. to keep things south a bit or then just north of LOTO around the Tipton area.
I've never been to West Plains, MO. but I can see that it is hard to get to and don't they have tons of hill's down there???? I know they do around Mountain Grove, MO.
I've seen somewhere that they had listing's of Ranches here on the net. If I come across it I'll let you know!!