I don't know if I've ever seen or heard of one. If they're around, they're super rare.
Kinda like how I've read of some Broncos escaping the factory with a Mustang V6.
They "happen", but they're not the normal stock setup.

 

It might have been made that way to use some of the last axles in the production line stock.

 

That was the assumption when the image of the 1980 build sheet was posted several years back.

 

And the earth is flat and the moon is made of green cheese and other ridiculous things.

Bronco II's came with V6's, no fullsized Bronco sold in the US or Canada ever came with a V6.

3.8L V6 installed in 1982/83 F100's. 1980/83 F100's were only available in 2WD.

 

I'm not saying there's any validity to it, just that I've read it. It was in a "history of the Bronco" I read somewhere (can't find it). A "there were rumors of some Broncos escaping the factory with a V6" Not that it was a regular option.
Point being sometimes there are odd combinations that make it off the assembly line, but it's not normal, or a factory option.