I had one that was a bit of a rescue, from Petco...they had it in one of those "river tank" things (duh, it's a WATER monitor...stupid petco), no basking light, and it was cold and skinny and half dead. So home he went, I wanted something small so he went into a 20G aquarium with versa-tops so I could keep in some humidity (not big on lizards in tanks but it was what I had...). Warmed him up nicely and 2 days later he was eating and on the road back. He remained very very shy & skittish as long as I had him (about 6 months). Due to circumstances I had to give him up (along with my other herps), so I'm not sure how big he's gotten now. Mine wasn't nearly as pretty as those pix though, his yellow markings were pretty subdued.
Oh by the way if you get one...they have some wicked teeth (mine never bit me, luckily).