The can be kept in anything - should they be is a different question.
Depends on the size of the rack. A FB or ARS 4 foot or more rack would work as would the Animal Plastics VE175 - although that one narrows out a bit on the bottom.
These aren't ball pythons - they are active and inquisitive and don't spend a ton of time in their hides. I would go no smaller than a 4'x2' enclosure.