The three prototypes were commissioned by Pat Mace (Central Ambulance and Central Services [trade embalming and livery service]) in Tulsa. He bought the '74 Fleetwoods and had them shipped to Ft. Smith for conversion. The center doors had Plexiglas windows that were stationary.
Charlie Ninde purchased these - along with a '75
Victoria, a '74
Sovereign Landaulet, and a '76
Fleetwood 75 - from Pat in 1978:
http://www.professionalcarsociety.org/forums/showpost.php?p=31010&postcount=44
We used the six-doors at Tulsa-Whisenhunt through 1989. They were great cars that held up well.