Hi Mike, I do know what your refering to, as a different species.
My first experience with them was a very long time ago, in the mid sixties, there was a reptile park by where I lived and I worked there part time. They had two giant water monitors, a normal and one they called a "Komani"(sp). The komani, was jet black and very large, nearly seven feet and bulky.
Then Glades brought in a lot of them. Robroy, told me and others, they were going to be discribed as a different species and were from a different locality. Thats is all I know about them or knew about them. I only told you what I was told, as I do not have them or wanted to have them.
Other then that, the ones I have seen have been nasty as all get out. But who knows.
Quatzel and some fella in Texas, have captive bred them, again all, FROM WHAT I WAS TOLD.
If they were bred commonly, I would give them a go. Kinda cool looking. Cheers