This isn't anything more than a chance for me to capture an idea that's been bouncing around in my head for a while now. A slight adjustment to the vision I had of Arcadia in my head turns it into the center of the Chinese Celestial Bureaucracy, rather than Mechanus. I also envision the divisions between the layers in this way:
A Great Wall guards the entrance into the plane from the Outlands, marking a division between the wild frontier and the start of "civilized" lands. A similar wall stands between all the layers. I imagine each layer as becoming increasingly less infinite (if such a concept makes sense). The Great Wheel is the wilds of the world beyond the Wall; Abellio, becomes the rural yet civilized frontier; Buxenus becomes The City; Menausus becomes an analogue to the Forbidden City, a seat of perfection sitting at the heart of Buxenus.
Access between the layers is only accomplished by passing through the gates of the dividing walls, and all people passing through will have been screened by the alignment reading petitioners. I'm not sure what kind of force prevents people from just flying/climbing over the wall. It could be that attempts to do so instantly draws the wrath of the Einheriar, who seem to zone in on anybody who attempts to skirt the rules.
Anyway, thought I'd put this out there to see if anybody wanted to play around with the idea. I think it still fits in with everything else that was talked about in the other thread.