Providing the same 16MP crop on a FF sensor would I think (if my maths is correct) require 26.6MP with the same pixel density as the Mk IV, so hardly a massive leap - in fact the same pixel density occurred last in the 40D.
Anyone know how sRAW is done on current models - would this be the same method for doing the 1.3x crop on a FF ?
All other things being equal, there is sense to it, 1.3x when you want it, FF when you don't. But hardly shaking up the market or their lineup, and not about to compete with the >32MP Sony / Nikon FF rumoured to be launched at the same time.
32MP would provide a 1.3x crop just shy of 20MP and a 1.6MP crop of 12.6MP but would require some good tech to match / better current high iso / low noise of the 1D IV.
Middle to end of August will be interesting, but I'm guessing lots more unknowns until early to mid 2012.