Sample images of the Nikon D7000 and Pentax K-5 have been posted over at DP Review. I've spent the past ten minutes or so at various ISO levels trying to analyze sharpness levels and color to explain the HUGE difference on DxO Mark (14 points for the Nikon, 16 for the Pentax) with the Canon's score of 66. I can't notice a significant difference at any ISO. If pressed, I'd say that the Nikon appears to be outperforming the Canon at lower ISO, but the Canon appears to win at ISO 12,800.
UPDATE: I was just looking over the images and have found a few places where both the Nikon and the Pentax handily beat the Canon at high-ISO. Still, there are a few other places where the Canon, especially the old 7D, seem to win. I'd call it a complete toss-up.
Canon EOS 60D Studio scene comparison (DPReview)