Even cheaper ‘starter’ straw bale home:
http://www.solarhaven.org/StarterStrawBale.htm

For our house I am thinking of a one floor structure that has 4 bedrooms, an office/library, a bathroom, a utility/laundry room, with the kitchen/dining/living room being all one big great room. I adore porches so I want a big porch, maybe even a veranda. And a greenhouse either seperate or attached to the main house.

Some more info/pics on SBHs:
http://www.greenbuilder.com/sbat/2001_Home_Tour

This woman and her two teenage sons have built a small, load-bearing straw bale house in the Sonoran desert near Tucson with earthen plasters and an earthen floor. She wrote a book about it! sheck out her house pics, her house is really pretty, especially the kitchen.
http://www.ahouseofstraw.com