Pininfarina-Designed Porsche 911 Prototype Listed for $1.25 Million

This rare, one-of-a-kind Porsche 911 offers a serious collector the chance to own a piece of automotive history. Designed in 1969 by legendary Italian firm Pininfarina, this prototype Porsche was developed to explore the idea of a four-seat 911—something the German marque never officially released. Now, the car is listed for sale on Hemmings for $1.25 million.

Originally delivered in dark blue, the car was later repainted in its current neon green, matching its wheels, and boasts a distinctive hunchback silhouette that immediately sets it apart. According to Hemmings, it was sold in 1974 by one of Germany’s largest Porsche dealers to a collector in Sweden, where it has remained ever since. This is the first time it has been made available for purchase in over 50 years.

Porsche had commissioned Pininfarina to explore the feasibility of a full four-seat 911, and the result was this one-off concept known internally as the 911 B17. To accommodate rear passengers, the design extended the 911’s wheelbase by 7.5 inches and raised the roofline to allow for additional headroom. The car weighs roughly 2,500 pounds but carries a noticeable rear bias, with 61 percent of its weight over the rear axle and 39 percent in front.

Hemmings describes the B17 as “the only Porsche 911 in the world like it,” noting that it represents a unique blend of German engineering and Italian styling. The platform never entered production, but the experiment laid the groundwork for future developments. In its listing, Hemmings adds, “Pininfarina’s work on the B17 demonstrated the potential for adapting the 911’s platform to create a different body style, influencing future Porsche designs.”

Though never intended for mass production, the B17’s engineering legacy carried forward. Porsche later applied some of the lessons from this project into the development of the 911 C20—a 911SC-based prototype that helped shape the company’s all-wheel-drive systems.

Despite its uniqueness, the listing is relatively light on imagery and technical details, though Hemmings claims the car is in good condition with 38,000 miles on the odometer. Still, at $1.25 million, any serious buyer will likely go far beyond browsing a few online photos before making an offer.