If you can't find one locally or Mac Van Pelt doesn't have the one you need you could try Bill Thomas Enterprises in San Bernardino, CA. He is all things rear end related. He did the re-gearing on a Ford 8 inch from a Maverick I'm putting in my '54 Ranch Wagon. He is a talker but worth a call or email IMO.
909-888-7049
www.billthomasenterprises.com I definitely recommend him for rear end work but not sure if he has the yoke you need. If he does and won't ship it PM me and I'll pick it up and ship it to you. If you send an email he will respond but it might take a couple of days. His shop phone is connected to his cell so that might be the best way to contact him.
One more suggestion: you might list at least your general location in your profile. That way someone in your neck of the woods might be able to offer assistance down the road.