There's a 'Hatchback problem" for american companies designing world cars. Americans prefer small cars as sedans, with hatchbacks being reserved for vehicles considered to be an SUV (and crossover). Most of the rest of the world prefers small cars to be hatchback. This preference is handled by established car companies building a lot of model variants. Tesla can't currently build a lot of model variants.
So with the M3, where does Tesla begin? With a model that best fits its largest single market, or the best world car? I think they start with a sedan followed by a crossover (hatchback), which is why these stories exist.
I wouldn't expect the crossover to be overly tall. Just a model that americans can claim as a small SUV, while satisfying the rest of the world's desire for a flexible four door hatchback.