You could also check out BARR'S, Moonstruck, and Precision cages. All good stuff.
One thing to keep in mind regarding heating -- if your cage will be in a regular room temperature environment (70-ish) you will need to use either heat bulbs or a radiant heat panel. Under-the-cage heaters like flex-watt, cobra mats, etc., will give you a warm basking area but will do little if anything to warm the cage air, especially if you use newspaper as a substrate.
Example -- I'm testing out belly heat right now in a new 24w x 24d x 12h plastic cage with very little vent space and a solid top. I have a thermometer probe under the newspaper on top of the belly heat source and the reading there is 95 (controlled by rheostat). That's fine...BUT...the thermometer in the cool end of the cage, less than a foot away, is displaying the same temperature as the room the cage is in -- 70 degrees; definitely NOT good. I need a cool end of about 80 or so. I have three thermometers doing this test (two in, one out), and no matter what kind of cage I've used in a good many years of herping I've had the same results with flex-watt type heaters. That's why I only use radiant heat panels.
If you have a specially heated herp room (around 80) that's another story. Then the belly heat is fine.
So, once again, I will forget about belly heat in my new cage and use a 12" x 12" radiant heat panel and it will be great.
Good luck with your new boa!
Bill