AMD is allowing their partners a lot of freedom with the 7970x2. I'm guessing that the meetings went something like this:
AMD Partners: "The Nvidia GTX 690 is insanely fast."
AMD: "What are we going to do?"
AMD Partners: "Why don't we take two of those 28nm tahiti cores and slap them onto one PCB? Call it a 7970x2."
AMD: "Good thinking. Will it compete with the GTX 690?"
AMD Partners: "We'll make damn sure of it... just let us mess with the specs a bit."
AMD: "Make it so!"
The card will likely compete with the GTX 690 in terms of speed and may even be a little less expensive. I'll see if can get my hands on one for review.