Have you had a chance to play with high-iso on the 60D... I'm starting to really believe the rumours of a tweaked sensor. I was playing around at 6400 tonight and my mind is literally blown out the back of my skull.
Either my 60D is the 'golden copy' or Canon really did a few little things no one noticed to their core tech. The AF has been flawless some 4000 shots in now... I can count AF misses on one hand regardless of lens (even the troublesome 50 1... well maybe two hands, but really some of them are most likely my fault for getting sloppy.
LOL, if they tweaked the sensor they'd be telling you, that's for sure. They wouldn't hide such a thing. It would be a marketing ++++. I don't know what camera you came from, but your results DON'T mirror those of Camera Labs, in their comparison of high iso on the 50D and 60D. They found that jpg was better on the 60D because the in-camera jpg processing increased sharpness and contrast, and probably did some noise reduction.
However, when raw shots were taken and processed in the same way, the two cameras were pretty equal.
I'm going to be honest, based on their test I couldn't tell much of anything the samples were tiny. I can tell you my iso 6400 is definitely usable and then some. I'm not talking luminance noise, but chroma performance. None of that ugly high-iso color weirdness (i.e. shifting, washed out, etc.). There have been things that have been said by Canon people as well regarding the sensor.
Finally, if they did, they might not want to scream it too loudly.. it would be bad for the 7D..
I'm looking to see a few more places run raws and do comparisons with some graphs and charts that I can look at.. ya it's measurbating, but we're talking minor differences really.