it was only built by Bertone. The designer was Giorgetto Giugario, who is famous for his design of the VW Golf 1 (1974). He also designed BMW 3200 CS, Fiat Dino Coupe, Lotus Esprit, Maserati Merak, VW Scirocco and many others. Some newer projects are the new Alfa Brera and Ferrari GG 50.
You can't dismiss the significance of the symbiosis between the designer and the carrozeria. Without Bertone, these cars wouldn't have been built and the stylist wouldn't have had the opportunity to display his talent.
Giugario's successor Marcello Gandini, to my mind at least, designed cars that have more visual and visceral impact than Giugario, but they're mostly supercar vehicles, Giugario's work has had much more widespread plebian impact with, as you say, the Golf, Alfasud, Isuzu's Piazza and Gemini, some early Hyundais, Daewoos, even Suzuki's little '70s Cervo coupe is said to be from his studio. Some of them have been pretty unexciting though. Is it an oxymoron to call a boring car design pedestrian?