Interesting topic. Just stumbled across it.
Couple of corrections.
The DC-10 that diverted was not Northwest, it was United.
B777 has never landed at DCA airport.
Delta used B767-300 before Obama's inauguration. I believe it was total of 8 round trips.
For a very short period, Eastern Air Lines operated A300 on a Shuttle flights between DCA and LGA. It was mostly a gimmick to get attention and passengers.
Orbis Flying Hospital DC-10-30 visited DCA June 28th 2016.
Boeing 787-8 demo aircraft visited DCA once. It flew IAD-DCA-IAD. Arrived at DCA on May 7th 2012, and departed back to IAD on May 11th 2012.
Vietnam Airlines 787-9 arrived empty at DCA on July 6th 2015 for official delivery ceremony. Departed the same day in the early evening hours.
I don't know of any other wide body aircraft visits to DCA