Matt, that pricing that you posted is when dealing with project home builders.
The costs for custom, architect designed homes is around the $1500-1800sqm.
In fact, I don't know if any that really build for less than $11,000 a square as a minimum.
I'm speaking from my experience here.
Custom and architect designed houses do things that project builders would never dream of. All that fancy stuff is what makes up the cost (no standard specifications that they can get suppliers to bid on for multiple homes)