I don't really agree, at least about the AF for future bodies being 'tested' in the 7D. The 7D does have a nice AF system, but at a basic level it's a straightforward bump to the 40D's AF - same dual-cross center points, same f/5.6 cross outer points, just 10 more of them. Spot AF, tracking modes, etc., are firmware mods. As for that being reactionary to the 1DIII AF fiasco, that was a hardware problem with the secondary mirror, and an APS-C mirror assembly would not effectively test a FF design.