A test shot taken with my new Canon Digital Rebel XT. The lense cap was on, and the Vt mode was selected with a 30" exposure. I count 14 visible bad "spots" (pixels?), but Photoshop's Histogram counted many (i.e., dozens/hundreds) of bright non-black pixels in the image.
This will make photographs of stars basically impossible, as there will always be bright blue/red/gray spots on every dark image.