Maybe from that one brand, but we still buy stock stuff from the warehouses as far as I know.
In addition to RockAuto you should try other local stores to you. There are probably twenty different brands of steering linkage manufacturers, with some using the same factory production facility, some being owned by one another, but enough of them independent from one another that hopefully you can find something nearby.
Otherwise you can purchase from the Bronco vendors in a pinch (here's ours:
https://www.wildhorses4x4.com/product/Left_Tie_Rod_6675yr/66-75_TIE_RODS).
Just might have to wait longer or pay more for shipping unfortunately.
Where are you by the way? Have many local sources to reach out to other than your first choice?
And no, I'm not aware of any other vehicle that would have anything even close to what would fit in place of a model made specifically for an Early Bronco.
Good luck.
Paul