Porsche is set to preview its plans for an additional Panamera model at the Paris motor show in September with the unveiling of a long-mooted estate version of its upmarket four-door saloon.

Billed as a concept by Porsche insiders and previewed here in our exclusive artist’s impression, the show car is expected to provide solid clues as to how a production version of a Panamera estate could look.

If there is sufficient interest in the Paris show concept, Porsche chairman Matthias Muller could grant it a definitive go-ahead as part of broader model expansion plans aimed at taking the company’s annual sales to more than 200,000 units by the middle of the decade.

While it’s unlikely to go on sale before 2016, the new sporting estate has been conceived following initial customer feedback that revealed demand for a more versatile version of the Panamera with greater luggage space than the nominal 445 litres of the current model.

The new Porsche, which is tentatively earmarked to form part of a second-generation Panamera line-up, would rival recent upmarket arrivals such as the Mercedes-Benz CLS Shooting Brake. It would feature an extended roofline, angled tailgate and fold-down rear seats to provide the scope for additional luggage capacity.

“It is one proposal we are looking at to increase the reach of the Panamera,” a well informed Porsche source told Autocar. “From the feedback we’re receiving right now, there appears to be sales potential for such a car in certain markets, especially Europe.”

Although it is expected to place greater emphasis on overall style than practical boot space, the Panamera estate would offer buyers greater versatility than Porsche’s regular sports car models. The role is already performed in part by the hugely successful Cayenne SUV and is set to be mirrored with the company’s upcoming mid-sized SUV, the Macan.

As well as offering the Panamera estate in standard-wheelbase guise, as previewed by the Paris show car, Porsche is considering a long-wheelbase version for selected markets in a move aimed at boosting the car’s suitability as a limousine.

However, a final decision on whether the new car will be built at all will not be taken until after the concept car has been presented to the public.

While Porsche is yet to reveal the facelifted version of its first-generation Panamera, the firm’s bosses are already well advanced with plans for its successor. It is set to share its underpinnings with various Bentley models as part of a recently enacted strategy mapped out by former Bentley boss Wolfgang Dürheimer that will see the engineering operations of the two companies work together more closely in the future.

As well as sharing the similar underpinnings, future Porsche and Bentley models are also expected to receive similar powertrain combinations. Porsche is set to adopt Bentley and Audi’s recently introduced twin-turbocharged 4.0-litre V8 petrol engine as a replacement for today’s turbocharged and naturally aspirated 4.8-litre V8, albeit in a unique state of tune.

Engineering of the Bentley engine was originally overseen by Wolfgang Hatz, who continues to oversee the Volkswagen Group’s engine development while assuming responsibility for development activities at Porsche.

Alongside the estate variant depicted here, Porsche is also said to be well advanced on a new two-door version of the Panamera in both coupé and cabriolet guises. It will be based on a short-wheelbase structure that is likely to be used on the replacement for the Bentley Continental GT and GTC.