My snakes aren't Giants by any means, but two of my Coastal Carpets have outgrown their 4 ft enclosures.
I just moved them them into the bottom two Animal Plastics T-25s which are 72L x 30D x 18H. The 30 inch depth really caters to Giants. I would have preferred 24 in deep, but I bought these new, unassembled off of Craig's List.
The bottom houses Lizzy, she is between 7.5-8 ft long
The medium is Mack, he is between 6.5- 7 ft long.
The top encl. is a used Boaphile for Punch, a 7 ft Boa.
I really love the drop down doors on the Boaphile, it is an old used model I picked up. It is flimsy compared to the AP. The top is sagging badly. I have heard that the newer ones don't sag.
The APs are heavy duty and thus much heavier than the unbelievable lightweight Boaphile. But not anywhere near as heavy as a comparable melamine encl. like the BoaMaster (not to be confused with Boaphile). I have a 4 ft melamine BM that is very heavy!
In all fairness, BM does make plastic as well. Their Mel. Encl. go up to 10 ft long. I don't know about their largest plastic.

Four ft BM melamine, it took two men and a little boy to place it up there!
Boaphile does make an 8 ft encl. by joining two fours together. Plus, they are all ready fabricated, so no putting together when it arrives (Except maybe joining the two fours).
While you do need to assemble the AP, they have a better selection of sizes.
For you, you may prefer the 7 or 8 ft encl.
There may be better ones out there, but the others I looked at turned me off by their websites lacking too much information and posed too many questions for me and had poor pictures. But that's just me, if a business has a poor website, I go elsewhere. However, the ones mentioned here could use improvement as well.
I am so pleased with the AP, I ordered an arboreal encl. for my Jungle Carpet and another T-25 to replace the Boaphile for Punch.
Happy hunting
