In 1935, Martin revised the XB-16 design. The wingspan was increased from 140 ft (42.7 m) to 173 ft (52.7 m), and a set of V-1710 engines added to the trailing edge. This version had a wingspan 20% greater than that of the B-29 Superfortress, the first operational bomber that would fill the role intended for the XB-16.
The XB-16 was cancelled for essentially the same reason the B-15 project was: it wasn't fast enough to meet the requirements set by the Army. Since both were cancelled around the same time, Martin did not have time to produce an XB-16.