Couldn't a fella just put a rotational device / coupling pivot between the trailer and the ball hitch, on the trailer tongue itself? Seems fab-able. It would allow the standard ball mount and only affect the trailer itself.
Heb Dduw, heb ddim; Duw a digon
I'm that gun-totin', farm-raised, evangelical, pro-environment, OHV ridin'/drivin', Southern civil rights pro-labor Liberal yo' momma told you couldn't possibly exist.