^This, monitors are better than fine in a large cage, the only reason to house them in small cages is it makes it easier to monitor their progress, health, eating, etc. I know someone who has his two baby Savs in an 8'x4'x4', and they're doing great. You really can't provide too big of a cage for a monitor.
Ryan, as far as taming.. Working with them, in other words force handling, makes them hate your guts, I'm not going to sugarcoat it. When they're young they know they can't fight it, and they just put up with it. Thing is, when they hit four feet they start realizing they've got a nice array of daggers and a bullwhip, and they can use them.. They turn into vicious beasties really really fast, and it's usually blamed on them "maturing"...
Best way to tame a monitor is to just leave them the heck alone, don't bother them, don't dig them out of their hides, nothing. Eventually they'll come to see you as a source of food instead of a giant moronic monkey that wants to kill and eat them. With time, they'll come to trust you, and some degree of interaction can become possible, but you can never force anything or you'll have a suddenly ticked off monitor in your hands... In other words, don't grab them unless you like to be clawed, bitten, and whipped by a six foot and very upset monitor lizard.