From Boeing Images:
Source:
http://www.boeingimages.com/C.aspx?VP3=SearchResult&VBID=2JRSN2AZURCA
EDIT: Attachment removed. See large image below.
Boeing 759-159 "Distributed Load Freighter" Concept
In the 1970s, Boeing studied the concept of a "distributed load freighter," a six-engined giant designed to carry containerized freight at a much lower cost per pound then was possible at the time. In the concept pictured here, the payload would be carried in two pods, one on each wing, each 26 feet in diameter and 150 feet long. The pods could be removed and replaced, whether empty or full, within minutes, and could be used to carry almost anything. Because of its landing gear width, it would operate only from airfields dedicated to air freight.
Source:
http://www.boeingimages.com/C.aspx?VP3=SearchResult&VBID=2JRSN2AZURCA
EDIT: Attachment removed. See large image below.