Being that this gpu doesn't use that many watts, half that of the 580 almost, I can see if they added some pwm stages and more power hookups, that this might be possible.
This is the usual for low end cards, not mid range ones though, mid range card's don't usually clock up 200%.

Then again the tnt, which was high end in it's day, overclocked over 250%...

Beats me, but a 2ghz ver super clock sounds cool to me.