This is the a full video ISO comparison comparing the new Canon EOS Rebel T2i (production model) with the Canon EOS 7D.
Note 1: It was mentioned in the video that the EOS 7D's autofocus has 29-points. This is not the case. The EOS 7D features a 19-point (all cross-type) autofocus system compared to the EOS Rebel T2i which features a 9-point AF system with just one center cross-type sensor for use with lenses that are f/2.8 or faster.
Note 2: The EOS 7D looked quite a bit more saturated on the LCD display compared to the Rebel T2i, however the actual saturation on both camera's were very similar.
Based on the limited testing inside my house it looks like both cameras are pretty comparable from ISO 100 - 1600 with the EOS 7D handling noise better at ISO 3200 and ISO 6400, though just slightly. The EOS 7D also looks like it might have maybe a 1/4-stop advantage in brightness at the identical settings. This seems consistent with my test that I did a while back when I compared the 5D Mark II with the 7D - the 7D looking to be a bit over exposed despite the exposure meter showing a middle exposure.
You can read my first impressions over at cameratown.com/news/news.cfm?id=8813