It was. And I can see the advantage of such a car. It addressed the biggest problem of sporty cars - limited carrying capacity.I can't think of a better way for Ford to have destroyed a brand - the Mustang - associate with youth, racing and fun than to have put out a Mustang station wagon model. Was that really something Ford considered?
GM also developed a couple of concept sports wagon such as the 1956 Corvette Nomad wagon.
More famously they produced the concept Trans Am Sports Wagon in the late 70's.
I remember this one. It was considered for production but was killed when the cost proved to be too prohibitive. The car did make it to television in 1979
European car companies have made production Shooting Brakes versions of their cars.
The most famous, and my favorite, is the Volvo 1800 ES from the early 70's.
BMW came out with Z3 coupe in 1999.
Even Ferrari has created a shooting brake in 2017 - The FF