Always there have been firms specialized on the design of car coachworks. This was much more common before World War II, though, because this was the time of the frames (Chassis). The body was in the hands of well-organized handicraft firms, along with the woodworks and upholstery.
When the self-supporting frames were introduced, handicraft firms vanished, or they managed to transform into industrial enterprises. They build Coupes and Convertibles, cars produced in low numbers, not profitable for the big mother company. An example of such a successful transition is the company Zagato Centrostile. In 1972 this company surprisingly launched a special, quite different body on the basis of the Junior Z.
It was all the more surprising as the shape of the Junior Z was highly appreciated. The production from sheet metal is so costly that the sales price of the Coupe is topped by 25%. But with its appealing shape the car found customers. The shape does not reflect beauty, it is rather provocative, and wants to win races. The whole racing apparatus of the GTAs is open for this car.