Keep trying. Those xmas tree tubs are usually seasonal, but you might get lucky and find someone with overstock. Don't rule out places like target, kmart, lowes and home depot.
I believe that BIG adults should be kept in "normal" cages.
However, these big tubs do quite well, for temporary housing.
I don't planon using them, but I think I'm going to buy a few of those xmas tree tubs, next year. It seems that they are always needed, when theiy're no longer available.
In regards to height, 12" seems to be the height of the shortest cages. That's an instance of stackables and optimizing the number of cages per stack. That works well for breeders and breeder hopefulls, who plan on housing many animals.
For a pet owner, the taller cages allow for a more asthetic view. They allow for climbing branches and such.
The thing to remember, is that "typically" BCI/BCC and a few others, are mostly terrestrial. So the amount of floor space provided to them, is very important. Taller is nice though, if you have the abundance of space.
On a side note, taller cages also mean more space the heat up. So they may take a little more heat, to maintain your gradients.
I'm just a novice myself. I hope I was able to provide some helpfull info. I apologize if any info is incorrect. I'm sure others can point out any corrections, if need be.
Good luck.
