I think the plated lizards would be your best bet, to be honest I'm not sure if you've got the experience you would need for a monitor..
Not to mention if you're looking for something "tame" a monitor would be about the worst choice short of a crocodile. Monitors can be tolerant, but it's not something to bet on. They're intelligent and very intolerant of mistakes in husbandry, not to mention almost all of them are not captive bred, and all that makes for a bad choice for what you sound like you're looking for..
If you must get a monitor, I would suggest a few Ackies, they will utilize every bit of space you give them.
Not to mention if you're looking for something "tame" a monitor would be about the worst choice short of a crocodile. Monitors can be tolerant, but it's not something to bet on. They're intelligent and very intolerant of mistakes in husbandry, not to mention almost all of them are not captive bred, and all that makes for a bad choice for what you sound like you're looking for..
If you must get a monitor, I would suggest a few Ackies, they will utilize every bit of space you give them.