Michael,
Some of the high ISO shots in your 1DMkIII article seem to exhibit some unusual artefacting - some would describe it as a "painterly effect". To me it's most obvious in the ISO 1250 shot of Cody. There is some visible in the flower shots, especially in the grey background at ISO 400 and above as well but it's not as obvious. To me it looks like somewhat "heavy handed" noise reduction has been applied. When looking at the high ISO shots on the Imaging Resource website I don't see this effect (e.g. look at the woman's hair in this shot - http://www.imaging-resource.com/PRODS/E1DM...SO1600_f50.HTM).
What was your workflow? Could it be a player? Maybe inadvertent Lightroom NR? Do the shots look like this out of the camera?
Regards,
Steve