I ignored the thread seeing the 7D in the title: I thought it was idle speculation about a distant follow-up to 5DII. Appears Canon doesn't really care about clarity in their numbering scheme
Seems like yet another incremental generation from Canon. Hopefully they'll finally have a working AF at least. TOP put it best: for a few hundred more you can get a FF A850.
I would think that a 1.6x crop factor means all you need to do is multiply the mpx of the 7D by 1.6 to get the FF pixel count. That works out at around 28mp which is close to the rumoured 30mp of the 1DsIV. I suspect this is going to be about the upper limit for the lens technology for most of the EOS lenses for a 35mm sized chip.
Somebody slept through geometry classes at school
For simplicity, let's assume the 7D has one megapixel 1cmx1cm sensor with 1.6 crop factor, for 1000x1000 pixels. Keeping the pixel pitch the same, we get 1600x1600=2.56 megapixels, ie. 2.56 times the pixel count.
I haven't done the math, but 47 megapixels for the FF sounds about right.