Just Like A Dog

Uhm... YOU CAN'T.

Sorry about that, but this is on you! You're going to need to ghetto rig this cage to the best of your own abilities. A lot of people use Plexiglas, Wood, or other strong materials. Typically, it isn't something that is portable(:

A ten by ten foot enclosure will suffice. A little less is okay, but it must be AT BARE MINIMUM the length of your monitor. It is best indoors, and if outdoors, your should keep it completely closed in. None of that winter air should come in. And, it wouldn't be 100 degrees inside that cage.

Your monitor cage should be about 80 to 90 degrees, have a basking area that is about 105 to 120 degrees, and 70 degrees at night. A halogen flood lamp can help you achieve the desired heat. Of course, you can always just go to your local pet store and talk to them about what lamp to buy, and how many. But, keep a thermometer in the room at all times so that you can insure it is warm enough, and not too hot.

Here is an excerpt from an article on  http://crittercaravans.com/Pages/Black-Throat%20Monitor.html .

Dirt provides the best substrate. It needs to be deep enough to allow the monitor to construct tunnels and burrows naturally. This provides not only security, but helps with regulating humidity and temperature. Go to places like Home Depot or Lowe’s and pick up non-chemically treated soil, sand, and peat moss. Mix the soil and peat moss (add water if needed) then add the sand slowly together until it clumps in your hand but doesn't drip. Fill the monitor's cage to a depth of two or three feet. You can also get mulch (cypress) and use that instead of dirt but be sure to have humidity gauges so that you can ensure proper humidity. You can buy a mister to spray if the cage with if it’s having a problem holding humidity. By using the mulch the cage will need to be sprayed everyday. You can also spray the top of the soil to ensure it doesn't get to dry which can strip the cage of humidity and dry out the monitor.

Humidity should be low, as they call Africa home, except in time of shedding. Then, increased humidity is a blessing. This only happens about three times a year, so(:

Though it's nice to offer a place for your monitor to completely submerge, it isn't necessary. More than that, they are arboreal. Mostly as juveniles, but still so as adults. Providing a tree stump would make a monitors day. (Of course, the tree stump should have a few strong branches.)

So, to sum it up.

A 10' by 10' enclosure. A modified indoor dog kennel, Plexiglas mini room, etc.

A 80 to 90 degree enclosure with a basking area of 105 to 120 degrees, and a temperature that falls to about 70 degrees at night.

Thermometer to be sure.

Substrate, and a lot of it.

Either a shallow pool, or just a big corner bowl to give your lizard a drink. 

And that's about it<3 Of course,

decorations never hurt. Vines, leaves, brush, and fake skeletons for a tough Lizard^-^