B&W Aregentine Tegu's get pretty big. You can look into an outside enclosure depending on where you live... They can become very tame but they need lots and lots of dedication to get them there. If you keep them in the cage and just interact to feed they can be quite menacing. However a tame tegu can be very rewarding and its almost like having a fat, scaled, lazy dog. If outdoor enclosures is out of the question, you can build your own indoor enclosure in such a way as to use the top as a table or to hold your other reptiles enclosures. I have seen pics of someone who built a tegu cage as a stand for an aquarium. IMO the best thing to do is build your own enclosure, (7x'3'x3') are good dimensions and if you go outside you can make it bigger/better.

HTH