Porsche will start selling an all-electric Cayenne coupe in late summer, the latest signal from the German automaker that it still sees market demand for EVs. The Cayenne coupe EV — which has four doors, unlike a traditional coupe — will join several other all-electric variants of the SUV when it comes to market later this year, including the base Cayenne Electric, Cayenne S Electric, and Cayenne Turbo Electric. Porsche does, after all, love its variants. And it could be its most successful. When Porsche introduced a coupe version of its gas-powered Cayenne in 2019, it took just a year for the sportier version of the crossover SUV to capture 20% of sales within the Cayenne lineup. Five years later, the coupe variant accounts for 40% of Cayenne sales, according to Porsche. In some markets, the coupe accounts for as much as 90%. In other words, the numbers suggest that the all-electric Cayenne coupe is a worthy bet even with its six-figure price tag.…