Not possible. Not even I am stupid enough to take apart a 1D.
IR doesn't need super fast AF and durability. It requires a high MP count and more importantly IQ. The fact the 5D is also FF appeals mainly.
I suspect by summer I will be running either a 5D mark II, 5Di or 1D, 5Di depending on Canons rumors of an entire new range this year which will include the 1D.
for the moment, 40Ds all around.