Carpet pythons, that cage would be perfect(although they could use some extra height). They are a snake that is always exploring and getting into trouble and they get to a decent size.
My female JCP just shed(as in 5 mins ago) and her shed was 6 feet 11 inches, so shes around 5.5-6 feet long and i can easily handle her with no problems. Mine is also in a 3x2x2 PVC cage.