Well... Thanks for mentioning the Quonset hut. I have relevant experience.
When I was in the one-time Republic of South Vietnam, I hung out with Catholic and Buddhist relief NGOs (I was a civil affairs officer). Oh, and I lived next door to the Quakers.
The Catholic school in Long An province made a library from a Quonset hut, and they put it on a stem wall about 2ft high. It made a world of difference in the interior space.
Then I came back to The World and was making geodesic domes on stem walls.
Also, I designed and built a garage for a retired Colonel in Cedar Grove, OR; the building department there gave me a detail for the slab and [post and beam] wall. Sink 4x4 or 6x6 posts for the [stem] walls. Nail form boards to the inside and outside of the posts. Pour the slab and stem wall monolithically, and strip the forms.
The only thing I would do additionally is paint the posts with epoxy just before you pour the concrete, to prevent water penetration. Other than that it worked great.