Tom Doak,
I had heard a number of rumors about Bethpage, including one about lengthening the 15th hole, which would seem difficult to do, given the road behind the current tee, and the steep drop off behind the current tee.
I don't know that a link has ever been established between Rees Jones and the lengthening of the 15th hole rumor.
I would be opposed to any effort to lengthen that hole.
Instead, I would create the same runoff feature at the rear of the green that exists on # 3 green and penalize any shot hit long.
Unfortunately, I think the area behind the green has been used for grandstands. I would further offset them, creating penal problems for balls hit long.