The porsche panamera looks like that on purpose. One of the main porsche guys, can't remember who exactly, basically said that he as a 6'4" tall guy, should be able to sit comfortably in the back seat. They built the car with the rear seats in mind. Unfortunately there is just no way around the ugliness issue with keeping the same dimensions of the car, the only way to combat it would be to make the car longer in the rear, and increase the wheelbase, which of course presents a host of other issues.
