Well I'll be go to hay. The house we saw was pretty big -- really big. And it didn't have stucco or cement or anything but bales walls (outside, at least). But there's no question -- the house was made of bales of something. Now if it had been in northern California the bales might have been locally-grown weed, but I'm pretty sure it was regular straw (from the color, not the aroma).
Thanks for the information, ladies and germs.