Sorry, not doubled, only 1,33x more.
Btw DMR images are even better than those from 1DsmkII as far as dynamic range and tonality, acutance is better due to lack of AA filter and overall they compete pretty well even for large prints. We are talking about 1,37x 10.5 Mp vs full frame 16.7 Mp.
But if you judge the quality of images only by the noise at 800 and 1600 ISO, well.. yes, Canon has top sensors.
Btw I'm not biased, as I have 1Ds with many L lenses plus a wonderful R-D1 with some CV and Leica ones.