Well so far FT, I've put in about 6 calls to places that specialize in collectable autos, and each one is giving me the name of the next guy.(you know how it goes) One guy at some place in Pearsonville CA,(whereever the heck that is?) who sounded like he knew what he was talkin' about, told me that those babies are like hen's teeth nowdays, as they have a tendency to break, and all the door handles off all his early '70s Riviera were long gone.
BUT...I've just talked to a guy at a place called Turner's Classic Auto Salvage(1-888-212-0918) who said he'd check and see if he has one, and he said he'd call me back in about an hour from now and let me know.
(so keep your fingers crossed, dude!)