As I mentioned at our last club meeting, I have been working on a paper that argues for a reconsideration of DX and contesting antennas for the low bands. This means that a smaller site would be required for any replacement station for Quartz Hill. I argue in the paper that phased vertical arrays make the most sense for 160m through 30m for a NZ DX location. Any site larger than about 1Ha would be adequate to build a collection of such arrays.
You can download the paper on the ZL6QH website.