I've never heard of the 1956 Cadillac View Master before

This Cadillac wagon was actually commissioned by the automaker. The grocery-getter was designed and modified by Hess & Eisenhardt, a coachbuilding company from Cincinnati, Ohio. The firm made a name for itself by manufacturing armored vehicles in the late 1940s but began producing civilian automobiles in the 1950s.

Dubbed View Master, this wagon is based on the fourth-generation Series 62 and was one of only a few produced in 1955 and 1956. It's unclear exactly how many were produced, but most sources say around 15 to 19 were made and sold.

The low production number likely has something to do with the very expensive price. Unsurprisingly, some of these wagons were purchased by celebrities, including actors Dean Martin and Burt Lancaster and boxer Joe Louis. Far fewer examples have survived.

https://www.autoevolution.com/news/1956-cadillac-view-master-is-one-of-7-built-owner-waited-30-years-to-buy-it-247365.html#