That book looks interesting, thanks. The Natural Building Blog site (whose authors have also written books on it, the late Owen Geiger and Kelly Hart) has some posts on building codes. Most of the blog's reports on legal success are about strawbale and cob, but they mention (expensive) engineer approval for earthbags, which is always an option if you can't escape to a free county or need to get cohabitants to trust it.

I remember a documentary on those desert dwellers. Unfortunately, their outcast society precluded cooperating on a decades-long proof of concept like the original tire-rammed earthship. And I guess they were too mobile for earthbags to work.

The late Monolithic Dome Institute guy sparked my imagination with his experiments with basalt roving and reinforcement on small, strong domes that don't take moving tons of soil to build. But even easier, Aircrete Harry plans on building multiple lightweight domes on his property, and he can pour his mix, instead of using a bunch of expensive and fiddly spray equipment. He's living my dream so far. Though before I start sewing together airforms, I want to try slipform or cast aircrete building. These techniques seem like the cheapest, most-effective ways to throw up durable structures, which can be reinforced with a denser mix later for burial (or built on top of a stem wall for partial burial). But all I've done sit back and watch so far.