EOS 5D Mark III vs. EOS 1D X - Differences?

[neuroanatomist]

Now for an affordable ef-s version of the 500mm F4.....

Indeed. Canon would save about $2 on the production cost of an EF-S version vs. the EF version - the cost of the white paint and the red ring. I'm sure they'd pass along at least 20% of those savings to the consumer. Such a deal.