Wes Rice might have large quantities… or may be able to direct you to a source:
Wesley G. Rice.
Address: 333 Braden School Road; Ponca City, OK 74604
Telephone: (580) 765 - 7049
E-mail: wrice@poncacity.net
Tom Circle might have seednuts available(I see they do offer Kanza and GreenRiver nuts) - I don’t see seednuts listed on their website, but I got my Kanza scionwood from him years ago.
While you’re at it, contact Clifford England at England’s Orchard/Nursery - he may have or have a line on Major seednuts. www.nuttrees.net