Mount Tamborine, it is. Used to go up there for camps and stuff as a youngster. It's probably about 20 - 30kms from the theme parks depending on which one your kids want to go to.
I didn't realise that future Expo's were meant to be held up there; sounds like a pretty good idea though.
Any idea of how many pins will be up and running at once? I imagine he would have to rotate them around as floor-space for 2000 sounds a bit expensive!