I am getting a head ache. I really, really want to help but it just seems like you are dead set on chams. If you truly love them that much then I am sure you don't mind spending a couple hundred dollers on an enclosure. Don't get me wrong it is great you love them so much but maybe set them as a goal. You asked for advice on what everyone thought would be good. Everyone says if you are set on the rubbermaid housing not to go with a cham. Pick a snake! They are way easier to take care of and you will have better success in the long run if you decide to breed them. I still think corns are the way to go but if you do not like any of the two hundred or so phases then maybe consider ball pythons. I really like the rosy boa suggestion also. Please take the advice of your piers! I would have loved this many people to talk to when a I started out! Take care and hopefully you will make the best decision for you as well as the reptile (whatever it maybe).