We heat ours with a 100w bulb and a big reflector on the roof facing down. We have to spray with water a few times a day but apart from that their pretty easy to use.
I havent got any photos of the set up as it jut comes out as a black rectangle on the photo when i took some before so i deleted them :? but the one we have is the same size you was after 48x30x30 with those bendy false vines and bamboo and false leafs inside.
Veiled chameleons are hardy and the easiest to look after. They can take a large variety of temperatures and humidity. Panthers are next but require high humidity all the time. Jacksonii are by far the hardest to look after, they don't do to well in captive conditions apartently