I didn't read through this whole thread now, but I think the correct strategy for "keeping your house cool" depends a lot on what kind of climate you live in. A strategy that's effective in Tucson is probably not going to work as well in Hawaii, and vice versa.
Here in Hawaii, I think there are two magic ingredients to keeping your house cool: Lots of airflow, and attic insulation. If your house is exposed to the trade winds and you are able to open up windows so you get cross flow through the house, you're going to be set. Insulating the attic (or adding PV!) to prevent the roof from radiating heat into the living space is the only other thing that you might need. Sun shining in through the windows, or even heating the sides of the house, is basically not an issue because the Sun is always very high in the sky and all houses here have 3,4, or even 5' eaves because of all the rain.
Now, if your house is sheltered from the trades, it will likely get miserably hot. The other viable strategy then is to seal yourself in and use AC, but that will be very expensive given power is $0.35/kWh.
This strategy works because while the Sun is strong here, the winds are always a pleasant temperature since they are regulated by all the water around. It's not going to work in an inland situation where the surrounding land heats up during the day.