Well, since no one else has answered this one yet, I figured I'd give you some advice. 
First thing, I have a few questions for you...
- What type of material will you be using? Wood? Glass? Melamine? Screen?
- What dimensions are you thinking of? Large? Medium? Just big enough?
If I were to build a single enclosure for a 4' ball python, I would go with a 36"x18"x18" wooden box with front sliding glass doors. The type of wood is up to you and how much you want to spend. I'm guessing this is more of a display enclosure so looks would matter.
Anyway, let us know what you have in mind and it will be easier to give you some pertinent advice.
-----
