In all due respect, there is some confusion here. A cold molded boat can be any combination of wood venners or wood veneers over strip planking. There is no one recipe for a cold molded skin. If you putn a core of foam beween cold molded skins then I would call that a "composite" boat. That is a very good way to build.
As for longevity: My cold molded NIGHT RUNNER just won it's class and was First Overall in the Swiftsure Race this weeekend against some very fast and fancy competition.
NIGHT RUNNER is 35 yers old!