The first Cadillac Eldorado Brougham was a one-off show car which made its public debut at the 1955 GM Motorama. This car was the direct predecessor of the ultra expensive, limited production Eldorado Broughams, which was built in 1957 and 1958. A pillarless four-door hardtop with center opening doors, and swiveling driver seat, the experimental 1955 Cadillac Eldorado Brougham incorporated some of the basic styling elements from the 1954 Park…