MD-12 ??

Did you know that :

The McDonnell Douglas MD-12 was a design study undertaken by the McDonnell Douglas company in the 1990s. Initially it was to be a stretched, higher capacity version of the trijet MD-11. The design then grew into a much larger aircraft with 4 engines and two passenger decks extending the length of the fuselage was announced in April 1992. This was similar in concept to the future Airbus A380 and Boeing NLA, and would have been larger than the Boeing 747. Despite aggressive marketing, especially in the aviation press, no orders were placed for the aircraft, and it was quietly forgotten after the 1997 merger between McDonnell Douglas and Boeing.

http://en.wikipedia.org/wiki/McDonnell_Douglas_MD-12