A 1971 Cadillac Eldorado Convertible has been listed for sale at $22,000 in Ponca, Nebraska, as part of a broader effort by a private collector to reduce inventory and make room for new acquisitions.

Cadillac built nearly 80,000 droptop Eldorado luxo-barges during the iconic nameplate's two decades of production. Ironically, the Eldorado was the last American-made convertible automobile in 1976, ...