Ray,
first, thanks for the entertaining fantasy about where you got your faith that 24x36mm sensor format is the future.
But about sensor noise, though this is not directly related to the 5D, I find it interesting that Sony describes the brand new CMOS senosr with 5.49 micon pixel pitch as having only 2.5 times as much dynamic range as the three year old Sony 8MP interline CCD with 2.7 micron pixel pitch.
That is
a) more than four times as much sensor area per photosite
three years of technological improvement
c) the change to CMOS, which is often claimed to be superior to interline CCD for noise levels
and yet instead of dynamic range growing by a factor of more than four as I half expected, it is only up by a factor of 2.5.
This suggests to me that probably either
a) well size and maximum signal level have indeed been increased by the expected factor of over four, but dark noise levels have almost doubled so as to consume about half of the dynamic range improvement,
or
the well capacity has not grown nearly as much as the available sensor area per photosite, due to a continuing disadvantage of CMOS sensors than a larger proportion of sensor area is taken up by other circuitry.