Wardair operated 727's YVR-HNL long before ETOPS. However in the early days of DC-10 & L1011 marketing, there was some reluctance to employ trijets for transoceanic routes -- some airlines thought their customers might not accept the idea.
There was never a regulatory problem, was there?
BTW - ETOPS applies only to twins - not to 3/4/5/6/8/10 engines!