I have never seen an anouncement of this sort so far ahead in advance. They might just have their %^&t together. Esp for the olypmics coming up. If anything I think it would be the D4 users that should be most concerned. Canon seams pretty cock sure of their product and themselves atm. Never seen that before.
@ neuroanatomist - About the shutter mechanism, I think you probably know more than me. Do they use the classic shutter with live view? I remember my old olypmus C8080WZ used to do 1/1000s with a decent flash (but low) output. Loved my 350D when I first got it. Got heaps of great shots with that. I screwed up the IR coversion of that when a few screws rusted after all the slat water splashes it copped.