Heh. In my 3e Campaign, my cosmology was esssentially the Great Wheel (including its version of the Inner Planes), but including a 3rd axis: Creation/Destruction. I never bothered with detailing the additional outer planes, as they never came up.
Two nested spheres - Creation lined up with the Positive Elemental Plane, Destruction with the Negative Elemental Plane, and that axis had a transitive plane with the Feywild as a sub-plane at the positive end, and the Shadowfell at the negative end. (Not that those names were used, but that would be the modern mapping.)
The other axes were also transitive planes - Ethereal was one, but I can remember if it connected Law/Chaos or Good/Evil. I don't remember what the other axis was called, but it wasn't the astral.
Because all of the planes rested in the Astral Plane.
Oh, and the various Material Planes spiraled around the Creation/Destruction axis, rising from destruction to creation, and then when it reached the absolute zenith, plunged right back down to the bottom. I'll see if I can't find my old notes/images for this.