also , in california, or at least the far northern part of cal where i have been living, we have the
Class K building permit.
it allows for alternative type construction if it looks solid and without any glaring problems. it will allow for simple normal type construction too,
i only know Class K is valid for Mendocino, Humboldt, Siskiyou and Trinity counties, i am unsure if the rest of cal has that or not.
this is not to say...oo well that california makes it incredibly easy, or that there arent areas where it would be difficult to build something unconventional, especially in the towns and cities and in places with high priced land.
but yeah you have to check with your local town by laws, and county rules. it is different every where you go, with rural areas tending to have much more easy going rules.
but i would consider to try to get the Class K permit in Cal, they will help you jump through the hoops of it, if you want to go that route...i think it's not that hard, just tedious, but one thing at a time and you could get a nice alternative structure permitted that way.