Yep. As you can see, Cypress XT (full shader HD 5800) setups are significantly stronger than a 6970.
If you don't mind CF profiles (and possible issues to a degree), I'd suggest a pair of reference 6970's.
You can have two for roughly $600, which would spank a 580 while having a stronger Volterra 8-phase Digital PWM (against nVidia Analog 6), more vRAM and the real-time XFX support. If you're willing to sped more, 580 SLi would be faster as you'd expect.
BTW Joe, enjoying the Extreme7? Was going to ask but always missed it when you posted right after me.