In the late 1980's I attended a Boeing conference where a briefing on the planned B777 was given. At the time I was not too concerned about the A310 and the A300 as they were regarded as regional operation aircraft. (The early Emirates services to MEL were operated by the A310 to/from SIN) Likewise the B757 and B767 whilst longer range were not capable of trans pacific operations (The B767-200ER was capable).
During the B777 presentation it was obvious Boeing were proceeding at break neck speed to introduce the go anywhere B777. Most pilots at the presentation where aghast at the prospect of a B777 being approved for say LAX-AKL and LAX-SYD. I was concerned about the prospect of up to 200 minutes nail biting on a single engine and the resultant engine bearing damage. (When a heavy twin suffers a shutdown both engines are usually replaced)
I suggested the B777 could have a CFM56 engine in the tail and be regarded as a tri-jet. The CFM56 would be used for take-off and shutdown at the top of climb. The engine could be shuttered for aerodynamic purposes when not required. In the event of a shutdown or worse the CFM would be fired up and provide centre line thrust and possibly electrical power and pressurisation. My suggestion was shot down by the Boeing attendees as being too expensive and adding weight to the aircraft.