Better chance of this happening than a Lamborghini four-seater.
For a time, the Porsche 928 was the intended 911 replacement, but 911 purists quickly forced Porsche to abandon that plan. As for the 928 grand tourer, it went on to live a long life, 18 years to be exact, before it was ultimately discontinued. But Porsche is in a prime position right this very moment to revive its two-door, four seat GT car. All it'll take is the greenlight from the all-powerful Volkswagen Group board of directors. Chances are, assuming the business case makes sense, it'll happen.
Unlike the previous generation Panamera, Porsche has already begun leveraging the new Panamera's platform to an even greater extent. Heck, it's already launched the Panamera Sport Turismo body style; why not slice the rear doors off as well? Makes an awful lot of sense, perhaps more so than that recent rumor about Lamborghini considering a four-seater of its own. That could happen, but it'll require an even greater investment and time, whereas the reborn 928 project already has everything it needs. Of course Porsche would come up with a new exterior design, which we've rendered here for your viewing pleasure, but the platform, engines, and all other major mechanical and technical work is done.
Ferrari has proven there's an upscale market willing to pay top dollar for a GT car, the FF and its GTC4 Lusso successor, and Porsche has surely noticed. Think about it. If a base Panamera begins at around $85,000, ranging to upwards of $200,000 for the Turbo, then a new 928/Panamera GT could potentially start off for around 911 money ($80k, give or take) and climb into the six-figures. It'll be profitable. As for the rumored Lamborghini GT car, sure, there's also historical precedent (the first Lamborghini, the 350 GT), but the brand is rather slow at launching something entirely new (see: the Urus SUV). Above all, Lamborghini isn't nearly as profitable as Porsche is for VW.
Beginning with the Cayenne, Porsche proved it could successfully break out of the niche mold and into the mainstream, generating huge profits with its growing lineup. Lamborghini has two supercars only. Why would VW Group take the chance on Lamborghini with a production version of, say, 2014's Asterion Concept, instead of that two-door Panamera? And, not to mention, money is tighter than it once was pre-Dieselgate. A reborn Panamera-based Porsche 928 is what's currently missing in Stuttgart's lineup. Different than both the 718 Cayman and 911, it's the front-engined V8 grand tourer that would make sense.