>>I only make custom enclosures for all my animals none of which are JCP's but I almost got some from Will Leary this year. He uses Boaphile for all his JCP's here is a link to his site just in case you have never came across it.
I was going to say at first that I didn't think that Boaphiles were a very good cage, until I took a look at that link. At least he's got branches and some of the larger Boaphile cages. Still, I think JCPs are a snake where a lot of people miss out on natural behaviors because of sticking with the old 'low and long' cage style.
Anyway, for making a new cage for a single animal or even a couple, I'd say try something a little different. Case in point:
This cage was set up to house a Coastal Carpet Python I had for a while.

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Matt Campbell
"I only went out for a walk and finally concluded to stay out till sundown, for going out, I found, was really going in." John Muir