Honestly, you boys and your maths!!!
with a 1Ds MkII you can crop into the image equivalent to a 1.3 crop body frame (ie 1d Mkii N, etc) end up with 12.8mp effective resolution*
You can crop in further and achieve a 1.6 crop body frame (30d, 20d, 400d, 350d) and end up with 10.44mp effective resolution*
You can crop into a 1D MkIII image equivalent to a 1.6 crop body and end up with 8.2mp effective resolution*
Right you may say, but my photography interests lean more toward landscape. Get more pixies then, says I, as this silly cropping nonsense is irrelevant
(*caveat to this is that its purely mathematical and the scientific explanantion will be slightly different because of Quantum Elephants and the fragile Space Time Continuum. It was actually in the development of the Canon EOS 1D mkIX GLX Sportif that an unfortunate paradox created the Bermuda Triangle. Or will. Or has but we dont know the reason yet. Grandma, my pills please)