Canon 50D Milestone

The recently introduced Canon 50D is a milestone camera: a camera that marks a new level of technical achievement in some way. Before I explain how, let me provide some background.
About a dozen years ago - I really can't remember exactly when it was - I was asked how many pixels would we need to equal what can be done with a traditional 35 mm camera. My answer was based on the best I could do at the time with slow black and white film: about 200 dots (pixels) per millimeter. For a 24 by 36 millimeter frame, that corresponds to about 35 megapixels. After consulting some Kodak information on colour film resolution, my estimate for a colour images was 9 megapixels.
When I commented (on Luminous Landscape) some years ago about the Canon D60 camera I indicated that the 6 megapixels of the D60 provided an image that was almost the equal of 35 mm colour film in some respects and yet characteristic of medium format results in others, especially grain-free smooth tonal transitions. In retros...