boaphile plastics (will have to search for the link I don't know it) has cages big enough for a full grown boa (even females!) but I think they're pricy. I'm planning on making my own cage (actually it'll be the hubby) so you might think about going that route. most people who keep boas end up making their own cages because it's more cost effective (though still pricy) and you can make it to your specifications. I know some who've made cages as big as 48long x 36 deep x 72 tall. She's an 8' something columbian and spends most of her time climbing on the huge branches he's got in there for her and he made it to fit in a corner of his living room. Mine wont be like that. Ideally I'm going to try to do 6Lx3Dx2H. I'm going to make it so I can stack other cages on top for other snakes!

Cages should be made of wood with plenty of ventelation. The acrillics and glass hold in moisture and will cause pathogens that end up there because of not washing hands before and after going in a cage or the air conditioner vent, who knows. I do know that In an a 75 gallon aquarium I had an adult pair of Brazillian Rainbows that caught a respiratory infection that got passed around and before I knew it I lost 9 snakes.
I just built a 4ftx4ftx2ft cage for my Surinam. I put a screen on the top and round vents in the sides. The doors are plexi with the hinges attached to the glass for an open look. I used Birch ply wood because it was nice. you need 3/4 if an inch to house a Boa, they can get very large and 1/2 inch wont do. Put heavy castors on the bottom that lock and swivel so you can move the cage with ease. I put a 31/2 foot thick branch so it was a foot or so from the wire top and my Suri basks at the top a lot but wont get burned. I heat it with 2 150w ceramic heaters one over the basking area and one in the middle leaving a nice open area for ventilation out the top. I did the outside in stain and polyeurithane and primed the inside and caulked the bottom all around and 6 inches or so up the corners then with latex enamel paint put 2 coats on. It looks like a piece of furnature. A 70 gal aquarium is $279.00 at Pet Co and you still have to secure the top with something besides the screen with books. I believe you should build what you will need for the whole life of the animal do it once and never have to wory about it agian. For about $200 I will have plenty of room to breed and the breeder told me to count on 8 feet and many get to 10 feet so I'm covered. I hope this helps.