"Pininfarina did many Cadillacs in the 50s ..."
In fact, Pinin Farina designed only ONE body on a Cadillac chassis in the fifties. It was a 3-pass. roadster commissioned by NY Ferrari importer, Luigi Chinetti. That car has survived, although in a slightly modified state. It is in the USA but I dont have its precise location.
The Eldorado Broughams of 1959 and 1960, although assembled in Turin by PF are Fleetwood designs designs.