I had forgotten the two greens on 6 at True Blue...Nice call there.
One of the holes at Threetops in Michigan has a double green. I believe it is two or three. A fellow built a course in Lockport, NY in the late 1980s/early 1990s and put two greens on one hole. Problem was, the hole stunk and you played directly over one green to get to the other. The pay-to-players who didn't get the concept started hitting pitch shots off the first green when the hole was cut on the second.
I believe (and Mr. Doak can confirm) that the reason for building dos greens on 9 at Pacific Dunes was simply that Mr. Keiser preferred one site, Mr. Doak liked another, and both were functional and changed the nature of the hole in positive ways.
Have you thought about expanding the green you already have, to add hole locations? I remember reading a quote from Mr. Nicklaus on learning green construction at Sebonack with Mr. Doak, to the tune of learning how to build greens from the inside out, instead of another way. Is the original green that bad? If you build a better one, won't the members want to play it all the time and abandon the first one?
My suggestion is, expand and enhance the first one if possible and see where the membership wants to go after that one. My suspicion is that someone played a hole with two greens and wants to force it into your home hole.
Paul and David, as I recall from True Blue and can see from Brainerd, it doesn't matter where you drive your ball in the fairway to play to the greens. Unless you split the fairway into two separate alleys, you don't gain an advantage of notable value. Arthur Hills designed the 17th hole at his eponymous course at Boyne to have two incredibly separate fairways (and teeing grounds) that gathered at the same green. It's a nice hole and all, and certainly a conversation piece, but is it necessary?