OP your only real chance at a Scar in the color you want is to either buy it second hand online or buy it in person. Most of the time online retailers don't post a picture of the actual rifle and you never know what you're going to get. One more option is to try gun broker because they are pretty good about putting up pictures of the actual rifle and decent prices can be found there if one looks hard enough.
I wish i had one. Fingers crossed for the 16s being a greenback. Dont know why but i love them. I forget who it was but one member here had one that was pretty damn dark green. Definitely the darkest i have seen.
My lgs had a black 16 in the past with a midnight blueish upper about a year ago. It was odd looking.