What are the shortest trips where single class, all economy seating is not enough?

Two classes... hard to beat Transrapid. Economy class 6 abreast, there is a first class at 4 abreast - for a trip lasting 7:30

Three classes... what about the JAL 777 First Class? You need something better than the J class 8 abreast 38 inch pitch seats...

What are the shortest four class services?