The mythical black Galaxy S III has been spotted couple of times in the past, the first time in Samsung's own Facebook pictures and the second time on a UK retailer's website.
Now the phone has been discovered spinning on T-Mobile's website among other phones that the carrier has to offer in the same shade of black. This one looks a bit different and has a finish akin to the white Galaxy S III instead of the fake brushed metal finish of the blue version. Then again, this is a render and shouldn't be representative of the final product.
You will find the phone in the link below. Just skip the intro video that appears in the beginning.