Nice analysis Erik. An alternate title could be "Who stole my six stops?"
And I think that Erik was merely using the JPEGs that Diglloyd posted. Analysis of the raw files might show an even greater advantage for the D3x photographic DR, which is clearly greater. The six f/stop claim in not credible. As expected, the Leica images are sharper due to more megapixels and the use of of a US $5000 Summarit-S 70mm f/2.5 ASPH Lens versus the $455 Nikon AF Micro-Nikkor 60mm f/2.8D Lens. Nonetheless, the D3x does pretty well, especially with deconvolution sharpening to restore sharpness lost by the blur filter.