It's kinda like those little puzzles you try to bet the ball into various tight places. What you are creating is a tank within a tank. When the juice starts going down, you gotta try to get that little ball (juice) into the center tank, past all the little holes without all running out, up to the top to keep the wicks wet. They would probably work much better if the wicks could run free. I tried making my tanks a while back out of syringes, and inserting the clearomizer through. They never worked more than half-..., and ended up being far more of a pain than they were worth. Better just to use the clearomizer as it was.
They used to have something called the Arry tank that held CE2s, but I think they are a thing of the past also.
I think it's the ceramic cup we're in love with. The new tank type devices like the T2, the stardust and the Vivi Nova are missing these (never had a Vivi, hope I'm not wrong!).
I got something a while back at DV that was called a CE5+. It looks like a Stardust, but the innards are replaceable. Unscrewing the tube from the base you are presented with an actual CE2 device, which is replaceable, much like the Vision Stone. I still got 3 tubes and about 15 coil units. It really works great, and none of the tubes show any signs of failing, so it ought to last a while if I need it to. The only drawback is it has a really tight draw. They don't sell them any more, though. Their new units have the coils like the Vivi.