Test of the Smoking Eye is in the Shackled City adventure path in Dungeon. I want to run it as a stand-alone adventure.
I'm running Eberron. In Eberron, there are 16 Planes of existence. Smoking Eye takes place in a level of the Abyss. The description of the setting makes it sound like Fernia, the Sea of Fire, would be the perfect place for it. But looking at the monsters involved, I'm not so sure. I've thought about making it Kythri, the Churning Chaos, but I'm still not sure.
If you were going to transplant this adventure from the Abyss, with monsters such as Slaads, Driders, Vrock Demons and Fiendish Centaurs, to a plane in Eberron, where would you put it? Or would you just put it in the Demon Wastes, which is what I'm also considering?
Is'nt the demons waste like the abyess? a set of plains that have the most terrabel think imaginable in it? that's what it sounds like to me and have the fallen parts of cellestia be peaces of a good alight plain...
Neither, in my opinion.
My inclination is that, due to the extremely alien and bizarre nature of Occipitus, I'd place it in Xoriat, the Realm of Madness.
Or, more specifically, a portion of Xoriat that once collided with Syrania and tore a portion of it away. As a result, however, it somewhat "stabilized", and thus isn't quite as far-realmsish as the rest of Xoriat.
Another possability would be that (though Eberron doesn't have specifics for such a thing) Occipitus is a "demiplane" of sorts...if you see the planes as "planets" that orbit the prime, think of Occipitus as a "moon" of Xoriat, that got dragged through Syrania at one point...or perhaps a "moon" of both Xoriat and Syrania, collided together and mushed into a single demi-plane.
If you go this route, you'll want to pull the focus away from the demonic and emphasize, instead, the utterly alien. Pseudonatural creatures in place of Fiendish ones, etc.
It's a shame that you're running it one-shot. The rest of the story is fairly good as well, and I could easily see Adimarchus trapped on Dal-Quor, and the possability of opening up another gate to there from Cauldron being a VERY solid reason for the PCs to seek to prevent it.