I might have missed it but I didn't see any pics or links on that site that showed houses made of this construction and the states that allow it. Could you post a site that has that info?
The pics don't show the whole, completed structure but it does show a brick wall. Is the brick wall erected on either side of the packed earthen wall? Does the roof rest on the earthen wall or on the bricks on either side of the packed earth?
Any chance you could show us the whole house and describe how the roof ties into the wall supports? Also, how thick is the wall? Is it wider at the base and tapers towards the top or of consistent width from top to bottom?
After looking a little closer it seems you have steel beam supports for your walls/roof. Is the packed earth more or less for insulation?
I'll keep searching! What state are you in and did you have to have a permit for this build? Was it easy to get or did you have to provide any special documentation?
I highly doubt it if I could get a permit, but that has never stopped me before. Honestly I think it would be a great project. I wish I could find a book more particular to my needs, rather than the one we both have read and communicated about. I mean, I'll never find a hill in this area, unless I make my own. But to have all those benefits....that would be great.
do some searches on earthbags. There are a a few good books on that style, and they work well on flat land. There are several websites with example plans and getting started guides, as well.