The Sigma DP1 Merrill and DP2 Merrill produce 14.75 megapixel finished images with more sharpness per pixel than any color camera on the market today. I like them both, see my in depth review of the Sigma DP1/DP2 Merrill for details.
The readers who have gotten either of these cameras have all told me they are quite pleased (there are some things that could be better, such is life).
Consider this: for $1700, you can get both cameras ($849 + $849) giving you a 28mm and 45mm equivalent which can share batteries and accessories and provide a measure of redundancy.
B&H has deals on the Sigma DP1 and DP2 Merrill as well as $500 off the SD1 Merrill.
(The Sigma SD1 Merrill has the same sensor, but it is a DSLR form factor, this is the camera that Sigma originally priced at $8000, it is now $1799.)
And you’re still at ~17% of the cost of a Leica M Monochrom system. And you get true color and superb monochrome! The reality is that I prefer the Sigma DP cameras to the Leica M Monochrom: even ignoring the enormous price differences, the Sigma DP Merrill cameras have autofocus, a high-res rear LCD, shoot true-color images or superb black and white, and offer ~91% of the linear resolution of the Leica MM. No, they won’t shoot as well in night clubs or dim alleys or that sort of thing, but with the money you save you can buy a Nikon D4 or D800E and solve that too with money left over.
The Sigma lenses on the DP1/DP2 are excellent, well they don’t have all the lovely qualities of Leica M glass, but they are better in some ways (little or no field curvature). And you get a lot more depth of field with the APS-C sensor.