I would suggest a side turned aquarium. It is very similar in function as a plastic enclosure (I have a few of both)

http://ball-pythons.net/forums/showt...arium-Solution

With this method you will not need the water feature. They can be balanced but it is a micro environment and difficult to grow the 'right' bacteria and keep the 'wrong' bacteria in check. I would avoid it unless you have experience in advanced aquarium keeping and understand that balance well. (having a healthy tank would help to add water and filter medium as with no food the bacteria die)

That is my suggestion. KISS method.