Re the home cooling. I think the biggest issue in Aus is bad or poor building design. The package builders just lay a slab, put up some walls, a roof and chuck in A/C. You can do so much with passive design, just think about all the old Queenslanders, and Darwin homes (pre cyclone), and old style Thai and Malay homes built to be cool before we had A/C. But it will require a custom build.
Decent insulation including double glazing will keep the house cool as well as warm- 30% or so of heat transfer comes through glazing. Shade the Windows, glaze them well. Other things like a central courtyard with water feature will cool the building core. Place bedrooms in the core, venting roofs etc.all help. Even just changing your habits like keeping the blinds and internal doors closed on a hot day.
For an idea of what can be done, My mothers side of the family own a brewery in the UK and built a 4400 sq m 'green' warehouse about 8 years ago. It's bloody impressive. Maintains a constant 11degrees C through 90,000 hemp and lime brick walls, a 0.6ha 'green' sedum roof for cooling, thermal buffering and water capture, air locks in the loading bay to stop heat transfer, shaded windows etc A lot of the principles can be adapted to a home but it's not cheap. It's saving them close to 50,000GBP in energy costs per year over their old traditional industrial estate warehouse
http://www.greensuffolk.org/sgbn/suffolk-case-studies/adnams-distribution-centre/
