That's the catch, it's free. You just have to go steal it from the BMW museum in Germany. They are still playing with the design so I understand so no mass marketing yet.
That's actually pretty common if you think about it.
Cadillac's designs were inspired by Buck Rogers' cover art. All those fins were supposed to look like how people thought space ships would look, with fins and aerodynamic bits.
As for Batmobiles, the other day I saw a black '72 Corvette Stingray.
If it had had fins over the back wheels, it would have been the batmobile! That was a really trippy moment.