Along with heavy, expensive plastic skin, the Ion "quad coupe" with two small hatch-like rear doors represents another failed innovation by Saturn. The rear half-size apertures couldn't be operated independently; they could only be opened after the front doors. The Ion disappeared in 2007, and the entire Saturn line followed it into oblivion two years later. Not General Motors nor any other American manufacturer has seen fit to revive the quad coupe since then.
