http://animalplastics.com/
Terrestrial cages, T8. its 48x24x12 I have my ball and corn in one each. I feel they are the best option. front sliding glass doors with locks, I use radiant heat panels (http://www.reptilebasics.com/40-watt-radiant-heat-panel) with a herpstat 2 (http://spyderrobotics.com/home/products.html) thermostat. works incredibly. my house is always somewhere between 60-80 degrees and this setup keeps the temps perfect (to whatever you set the herpstat) and the humidity sits between 40-60% depending on the substrate/water bowl size.
Sure an adult BP could be in a 36xwhatever cage, but I feel the extra space is appreciated. she eats well, doesn't seem stressed or restless but also roams around and stretches out. As for height, she was in a 36x12x18 glass enclosure (humidity was a struggle) and she would climb it and come crashing down, so I didn't like it much and figured more floor space less height would be better suited for her since shes not the brightest ;]
Anyway, Id recommend what ive suggested. the cages are PVC they will last as long as the snake is alive, they come with dividers if you has a small baby and want it to grow into the cage, and they will be big enough for the adult life. hope that helps and isn't confusing.