I would look at simpler cost effective ways to accomplish the same thing. At the time Ford was making similar things, their costs were different, the subcontractors available were different, and they would think nothing of investing tens of thousands in tooling.
If it were me, I would make a solid steel, either plasma cut or totally machined, hub to bolt to the rear end, (dunno about clearance- if there is a gear protruding, maybe two stacked donuts) then weld a standard pipe or mechanical tubing to it, and weld that to the adapter piece at the end. Of course, the other thing Ford had that you dont is a building full of engineers, and destructive testing. So what diameter, and wall thickness of pipe is a question. Perhaps 2 pipes, one larger diameter at the rear end side, and then another, smaller diameter slip fit halfway down, welded together.
I am assuming that if the original was stamped sheet metal, we are talking "historical" torque and horsepower numbers- a model T was 22 hp. Dunno what this needs to handle, but I would guess not Keith Black levels - If its for vintage autos with lower power, I think a welded fabricated assembly would work.
the typical modern approach would be to machine the whole taper from a solid forging, but no way you could get $200 pricing for that on 2 dozen parts. 100,000 a year, maybe.