Would a Porsche Cayenne convertible prove popular? We'll probably never know but such a vehicle was under consideration at Porsche shortly after the automaker launched the original Cayenne SUV two decades ago.

Porsche on Thursday revealed a Cayenne convertible design buck that was built shortly after the original Cayenne went on sale at the tail end of 2002, or close to a decade before Nissan revealed its Murano CrossCabriolet.

The convertible was one of three additional Cayenne body styles placed under the microscope, the others being a stretched version with third-row seats and a coupe. The coupe to some degree was finally realized with the current third-generation Cayenne in the form of the four-door Cayenne Coupe.

The convertible today sits in storage at the official Porsche Museum in Stuttgart, Germany. It's not a functioning prototype but a design buck referred to by Porsche as a Package Function Model, or PFM for short. You'll notice the tail is split between two different designs, as the design team were testing different options for the taillights.

Porsche Cayenne convertible concept

Porsche Cayenne convertible concept

The designers went with a two-door body and a targa-style roll bar at the rear that would help provide some rigidity with the roof removed. The interior is the same as the production Cayenne but the windshield is lower. And the convertible roof is an automated design that folds away beneath a rear deck that can be opened along two axis, allowing it to flip open to house the roof or be operated like a conventional trunk lid.

The idea of a Cayenne convertible never got past the design buck stage. According to Porsche, profit projections for the vehicle weren't promising, and there was also the issue of whether it looked attractive enough to wear the Porsche badge. The oddball styling of Nissan's Murano CrossCabriolet was no doubt a contributing factor to its demise.

“An SUV as a convertible is a challenge both aesthetically and formally,” Michael Mauer, Porsche's design chief, said in a statement. “An SUV always has a large and heavy body. You combine this with a small top half and then cut off the roof...you get very strange shapes emerging from that.”

Note, there have been two SUV-based convertibles launched following the demise of the Murano CrossCabriolet. There was the Land Rover Range Rover Evoque Convertible, based on the previous generation of Land Rover's compact crossover, and the Volkswagen T-Roc Cabriolet currently on sale outside the U.S.