I'm betting that will be the dodo of the classifieds. Unless something changes there is a significant chance that after the preorders are done and whatever small number of Zions he makes over the preorders are sold, there will be no more Zions. That would be very sad as I think it is one of the best vapes on the market, certainly the best I have used, but my love (and that of other owners) doesn't pay the bills.
I was expecting the preorder folks to be as effusive with their praise as the beta team was. As it has turned out, while Zion has gotten no real slams, and I think the new owners like them, they just aren't expressing their appreciation for the vape strongly enough to drive interest to the point where it makes sense for RBT to make the necessary investment of time and $$ to keep them coming. Part of it may well be the fatigue from waiting so long makes it a little hard for some to forgive. After all, this isn't like the HI where you know going in the list is long and so is the waiting time.
That isn't a criticism of RBT or his customers, it just is what it is, a sad fact of life. That being said, I suspect them to go VERY quickly if ever listed on the classifieds. If you want one, and you see one, I suggest you jump quickly. Personally I am so enamored by it I might jump myself just to have backup. And I don't even have my production unit yet.
Anyway, the only thing that might change this future is PDA. Short of that I recommend folks be ready to jump if anyone show interest in parting with theirs.
At least the heater lives on in Milaana and there are other things in the pipeline (like TimberCannon and the 510) but if Zion slips away we all lose a little...