I don't think anybody makes them. How many are stripped? Those are just regular nuts tacked to a plate held in by some sort of loose fitting holders(so they move around for adjustment). If yours are so bad that you were going to surgically replace them (as in cut into the A-Pillar) then just weld new nuts onto the old plates, Otherwise tap it to the next size and be done with it. Somebody may have a better idea that's just what I would do.
P.S. Your a new 1st Genner to me so lets see some pics of said truck