Although I wasn't bowled over by their K-7 Preview (which did appreciate the camera, mind you, just not in the most reasoned explanations), I'm more appreciative of these K-7 chart test results from Imaging-Resource.com and how they reveal the K-7's potential detail bonanza with a lens like the DA 70mm lens. Personally, I'm ignoring the poster test they do of the house (below left). I like the line tests and ISO tests best. What you'll see at their site is a set-up where you can compare the chart resolution tests of the K-7's DNG and JPG files versus images tests from other cameras like the Canon 50D. How does the K-7 fair? Better than I would have guessed just a month ago. The K-7 actually holds it's own very well against Nikon's mid-range and semi-pro lines when you're using low ISOs, and fairs pretty well 1600 and higher. This is a real contender.
ISO 6400 test with the Pentax K-7, original JPG here.
To see the comparisons for yourself at Imaging-Resource, visit their Comparometer™.