FWIW the Leaf C-MOST and its predecessor the Valeo 6 used a 6MP, 14-bit, 24x36mm CMOS chip. The Valeo 6 was a portable product and was able to shoot almost 2 fps 
Oh yes: IIRC, that was a sensor from Scitex that used the same FillFactory CMOS sensor technology as was used several years later in the Kodak 14N, and it was manufactured by the same foundry, Tower Semiconductor. Did it have the same good DR but bad noise at high ISO speed as the 14N?
Anyway, this is more evidence that a number of companies can design and fabricate a CMOS sensor in 36x24mm format, and anyway, Leica could also get a very nice 36x24mm CMOS sensor from Sony. The big question is the economic and technical viability of making a sensor larger than that, like 45x30mm for the Leica S2 format.
(The other question is why some people think that a newcomer to the design of large CMOS sensors would do better than Sony's recent efforts!)