Yes, I understand that...no noise-reduction was performed on the images on your part. However I am under the impression that cameras in the different categories of Canon's range handle noise differently. For example, the 1-series cameras tend to produce images that are more noisy but hold a little more detail whereas the 400D or a 40D chooses to remove the noise instead. This is all independent of the user's choice as to whether to apply noise reduction or not.
The noise reduction on camera that we actually have control of seems to be the 'dark-frame subtraction' method that is employed by the camera at longer exposures if we choose to activate it. But for exposures shorter than about a second or so, I don't believe this kicks in at all, even if it's set to 'on'.
Again, just my assumptions and impressions. Others may discredit this.
In short however, the images above show how low the chrominance noise is in a 40D image.