Originally posted by MrApollinax I think I read it here somewhere but the covered up buttons were for CF and SD. The original mock up had two slots one CF and one SD. However with the advent of SDHC and SDXC the decision was made to go with two SD slots instead. Good because it will free up some space on the overall body design, bad because now they have to make a decision of what to do with those buttons. If it were me I'd loose the two buttons and make it a single button to toggle between the two SD card slots and then cost reduce the crap out of the body to drive up margins. Then again that would just be my thought process.
Rather than toggle between cards, one could be the buffer and one could be the permanent storage. Mind you, I don't see the 645D being used in rapid-fire sports photo mode too often.
Jack