Becky said "As for snowload, the architects could easily address that for you and would probably go to bat for you with local building departments."
Think again! Architects, Engineers, and building departments fight do-it-yourselfers. I know because I have been looking for their help in my project to build a cement bubble house. You can imagine an engineer or architect looking at your idea and thinking, "oh yeah, right. I'm just going sign my name and let this person who has no experience, no credentials, and a shoestring budget use and perhaps damage my hard earned reputation to make something that I have virtually no control over."
If you plan on building something besides a conventional box with conventional materials you better gear up for a long running battle with the building department. You'll have to do the math and convince everyone it will work, including the architect.
The comment about 9 parts dirt and one part cement being structural is not correct, even with barbed wire. Dirt does not make solid cement. Firming dirt over your head is not structural cement overhead. Structural concrete for overhead work is pretty rich and dry - like one part cement two parts aggregate, less than 1 inch slump. The aggregate must be clean - no dirt. There are pretty tight restrictions on the reinforcement, and some barbed wire snaked through isn't adequate.
Don't get me wrong, I love alternatives to boxes. These sandbag structures and other curvy buildings are inspirational. I am going to build some, but, initially, they'll have to be outbuildings to dodge the objections of the professionals.