I think another "twin" ,though not etops, ditched also due to fuel exhaustion, a DC9 quite awhile ago.
I seem to recall a 4 engine plane landed in the water in the bay of San Francisco. a JAL DC8 back in the late 60's or early 70's... the plane was recovered and lived to fly again...though not a true ditching I suppose.
Until there is a regulation for everything, keeping the passengers, crew, and innocents on the ground safe and the reputation of your airline clear might be good advice regardless of the number of engines installed.
j