Cadillac didn't offer a factory station wagon in 1969, but if you were a deep-pocketed celebrity like Dean Martin, you could have one specially built.

Now up for online auction in Australia with Donington Auctions, the late singer's 1969 Cadillac Eldorado Custom Sport Wagon is a one-off built by George Barris, creator of famous television and movie cars like the 1960s Batmobile.

In addition to the custom wagon body style, the car, dubbed Casa de Eldorado, features a two-tone white-and-gold paint scheme, power rear hatch, and front-fender humps meant to simulate spare-tire carriers. This is the only known Barris-built 1969 Cadillac Eldorado wagon, although he is thought to have built a similar car based on a 1970 Eldorado for Frank Sinatra, according to the auction listing.

The wagon is based on the eighth-generation Eldorado that debuted for the 1967 model year. This was the first Eldorado with front-wheel drive (an unusual feature on American cars of the time), with hardware borrowed from the Oldsmobile Toronado. Power is provided by a 429-cubic-inch V-8 connected to a 3-speed automatic transmission.

Ex-Dean Martin 1969 Cadillac Eldorado Custom Sport Wagon (photo via Donington Auctions)

Ex-Dean Martin 1969 Cadillac Eldorado Custom Sport Wagon (photo via Donington Auctions)

Before the Escalade, several companies offered coachbuilt Cadillac wagons to cater to wealthy car buyers looking for added utility. American Sunroof Corporation (ASC) offered its own Eldorado station wagon in the early 1970s, while Traditional Coach Works Company had the Castillian Estate Wagon, based on the Fleetwood Sixty Special Brougham sedan. These conversions were expensive, though, so only a handful of each were made.

The Dean Martin Eldorado was exported to Australia by an enthusiast with a penchant for American cars, but was later sold and neglected, according to the auction listing. Consequently, while it still runs, it needs some mechanical and cosmetic work.

The estimate is between $25,000 and $35,000, in Australian dollars. That translates to between $16,350 and $22,900 at current exchange rates.