I get to see a lot of over-the-top clubhouses in my travels. The last two were Nanea and Kohanaiki in Hawaii -- the first one probably in the size range you asked about, the latter 70,000 sq ft and $70m. They were both great for their respective situations. Everything we saw in South Korea was off the charts, too, in one way or another, but NOT small.
Clyde mentioned Tara Iti and I think that clubhouse [and how it integrates with the golf course] is a big reason the course has been so highly ranked. A lot of it is indoor/outdoor, because the weather in N.Z. is so good. Most architects are afraid to get the clubhouse too close to the course, so it winds up being too far away, and not part of the course. We worked hard to avoid that.
P.S. Now that Bel Air has finished rebuilding their golf course, they are in planning to tear down and redesign their clubhouse (!). I have not seen a plan, but based on the various people they've spoken with, I'd guess it is going to be pretty spectacular.