Well, even if you do go with a cage of those massive dimensions, it would be more than enough room for say, something the size of a large adult female
BCI. I have to agree, the
BCIs are awesome snakes if you can house them properly, a cage with about half of each dimension would house one comfortably. Keep in mind, a lot of the boids (especially the larger species, i.e.
BCI/BCC, burms, etc.), as they become adults they spend much less time climbing. So, all that vertical space would be a waste, even if you put in shelves. Have you considered one of the carpet pythons? They tend to be a bit more arboreal as adults than other pythons (even 8'x4'x3' is quite large for even the largest carpets). I think they're great snakes, personally. The Brazilian rainbow boas really interest me, but you have to be prepared to provide a lot of humidity, as well as a beautiful snake that spends a lot of its time in hiding. Don't forget about the colubrids, there's a lot of great snakes in that family as well. Good luck in your search.
Bry