As far as I know "Telyt" is using a Leica DMR so it's a 1.3 crop factor digital back with a Kodak CCD. I don't know the pixel size. I also know that "Telyt" takes very good pictures, so whatever the bits, the camera serves him well.
The S2 is a very good camera and Telyt is said to take excellent pictures. However, his image quality is likely related to factors other than the bit depth of 16. Your DR analysis of 11 - 12 stops would require a bit depth of around 12 bits for encoding. One can reach similar conclusions through a noise model similar to that used by Roger Clark
where the two main sources of noise--shot noise and read noise--can be added in quadrature to obtain total noise. As Emil
has explained, it makes little sense to quantize the signal from the sensor in steps much finer than the level of the noise.
The Leica S2 uses the KAF 37500
sensor which was designed specifically for the S2, and Kodak has not released a data sheet. However, they do state that the chip uses the 6.0 micron TrueImage technology, and the performance is probably similar to other chips in this series. The KAF-40000
is one of these chips and it has a full well of 42K electrons and a read noise of 13 electrons. The DR is listed at 70.2 db (11.7 stops), in line with your estimate.
The chart below shows the Clark style noise model along with the sensor gain (electrons per data number [DN]) for various bit depths, assuming that the full range of the ADC is utilized. At a SNR of 1, total noise is 13 electrons and even at a bit depth of 12, the gain is 10.25 electrons/DN. This meets Emil's criterion. A bit depth of 14 would give a margin of error, but a bit depth of 16 serves only to quantify noise.