Concept cars let designers go wild ... It had four doors that opened automatically, with the front pair sliding forward while the rear slid backward (removing the need for a B-pillar).

Kia came to SEMA with a reworked concept ... rear door porch; a sliding right middle door that reveals a B-pillarless opening ...

Two years ago, Cadillac absolutely floored us with the debut of its gorgeous Ciel concept at the Pebble Beach Concours d'Elegance. And since that droptop four ... The front bucket seat slides ...