Since I am new here I am not sure how much my opinion counts...but I have played a ton of these nicer courses we all talk about and so many wish to play.
I think to get into this you really need to say what is exclusive? I cant say that Fisher Island, Naples National, Metidiconk (?spelling sorry), Hamilton Farms are so exclusive. These courses are great, I have not played Hamilton Farms though, but becoming a member is not that hard if you have the funds. I mean, two of these at least advertise in magazines about membership! These extremely great courses in the world that we praise and write about, not all are exclusive by any means. And that really goes for a long list of the top private ones as well.
If you look at some of the courses that have hardly any members, are the courses that good? Or is it just the thought of a few owners that own a course? If I bought a muni course in NJ today and did not let anyone play it at all, would that be considered a real exclusive course? I have played one of these courses that some have heard of (outside of tri-state area) and was not impressed at all.
And then you have some amazing courses that I am certainly not naming where we all know you can get it 9 times out of 10 if you are black, jewish, or anything that is not there ideal. And that sadly consists of a very big number on the list of top 100.
So, it is interesting when I am reading what is considered exlcusive and not. Just my opinion. and with that I would say Augusta and Pine Valley from what I am thinking off the top of my head are the "exclusive" courses of the world, or at least America.