My guess is that the 7D will be next year's big upgrade product, mostly because at the moment it's still holding its weight, and maybe more importantly its user base does not yet feel it's getting long in the tooth. The 5D and 1Ds on the other hand do and from a marketing point of view that's the time to replace them. In my opinion, barring actual development issues, they will probably be released not too far apart from each other with the 1Ds being first. Canon hopefully learned from their mistake and will differentiate the cameras enough for the 5D not to cannibalize its big brother. My hope is that they'll do this by bumping the hell out of the 1Ds and not by holding the 5D back.