I don't know if anyone else has seen one but I have not. I have seen: 1-3/4", 2" and 2-5/16", 3" then a Pintle Hitch and 5th Wheel but never a 4" hitch.
1-7/8-inch ball has up to up to 2,000 lbs capacity and features 3/4″ or 1″ bolt (shank) diameter;
2-inch ball, which is the most popular size, offers capacity from 3,500 lbs up to 8,000 lbs and features 3/4″, 1″, or 1-1/4″ bolt diameters;
2-5/16-inch balls can handle from 6,000 lbs to 40,000 lbs and come with 1″ and 1-1/4″ diameter shanks;
3-inch balls are used infrequently for heavy-duty applications.
Pintle Hitch Capacity: Up to 60,000 lbs. Couples to a lunette ring. Available for heavy-duty vehicles.
Might be a 4” drop used on some taller 4x4 pickups.
My wife’s new ram has to have a 6” drop.
This must be a eastern thing to remove the male stinger part of hitch.
I doubt there are a half dozen pickups in Oklahoma that don’t have one on constantly.
Solution. Don’t crowd the truck.