My parents house had a 36" fan in the side of the house and we used to pull down the attic staircase for ventilation. That cooled the house down great. That is what got me started on this. Unfortunately, the side without windows doesn't have space for one. 1/2 the side is the garage, and the other 1/2 is a fireplace with my TV on the wall and custom bookcases on the walls around it. Just no way to do it.
I personally don't like the big vent in the ceiling so thats why I never looked into the fans. My neighbor has one of the big fans and they barely use the A/C at night. Its time to do it. I was going to put one of the big ones in, but it would be right over the bedrooms and I don't feel like listening to it at night. This unit will be mounted away from the bedrooms and should be relatively quiet.
I also have ceiling fans in 4 rooms which I use, but it still doesn't draw enough outside air.
This was the other one I looked at,
http://www.wholehousefan.com/PRODUCTS/HV1600-GR.html but I think I'm going to give the AirScape a try...