Thanks to Sky at Vicaso for passing on the link to this Canon news.
A recently published Canon patent application (see USPTO Appl. No. 12/630,594) reveals a method for altering exposure values at the pixel level, which would allow Canon to produce a camera that captures a much wider dynamic range with a single image.
The lengthy patent application spells out a process whereby the camera captures a preliminary image with normal exposure values and then evaluates the exposure level across the entire image. After creating an exposure map of the scene, the camera alters the exposure amount at the pixel level for the primary HDR image capture.