You migth be right, but I cannot figure out why. Any hints?
The Kodak CCD sensor used in the Leica DMR does indeed seem to have great DR, even if its high iso noise doesn't seem to be on par with the Japanese sensors.
I am glad to here that about the Leica back: on paper, the new Kodak MF sensors have the same pixel pitch yet almost one more stop of DR and modestly improved noise levels.
Naively, the larger electron well size of FFT CCDs compared to CMOS (at equal pixel spacing) gives both more dark noise (counted in electrons) and more well capacity (again in electrons), leading to
1. lower usable minimum Exposure Index ("ISO") due to extra highlight headroom
2. better S/N and DR at minimum EI, due to that minimum being lower
3. higher dark noise when compared at equal EI.
Conceivably, the major customers for the big Kodak and Dalsa sensors care more about resolution and DR at low to moderate Exposure Index than about noise at high EI. In particular, I think of MF as oriented to controlled light, with flash, studio light, tripods and such; not so much for snapping action in low light without flash. And perhaps the same when MF means Manual Focus, as with the Leica R back!
I am fairly sure it is a matter of FFT CCD vs CMOS, not USA and Canada (Dalsa) vs Japan.