I saw the proto type of this lens in March in Japan. At that time there was a thought of making a {very) small run of these lenses with a Contax C-mount, but Zeiss was not really interested (at that time at least).
The formula in the lens is the ZM lens adapted to the S-mount. I dont know if it is going to be markedly better than the Millenium 50f1.4, but I know that Mr Kobayashi used the Nikkor lens as a bench mark for the Sonnar design. It is not as simple as it sounds to translate a M-mount to a S mount as you are dealing with different back focus issues and a completely different mounting system. The benefit of the Contax.Nikon mount is that you can make the lens a bit more compact as you dont need an internal helicoil in it.
When the ZM 50f1.5 came out I know that given time, Mr kobayashi was going to make it in the S mount. He is a dedicated Nikon fan and the opportunity to adapt a truly classic design with upgraded glass and coating was too much of a temptation.
The arrival of the S3 Millenium and the SP 2005 has created a renewed interest in the classic S and to some extent the C mount lenses and Cosina's S mount series of lenses, though not huge sellers (there were never expected to be that) has shown that there is a small, but dedicated market. In spite of digital running amok, there are still small pockets of shooters who like to use film. I always feel that with an "analog" camera you take a picture, with digital, the camera performs a multi task operation. Mr Kobayashi has single handedly revitalized the range finder market in the last decade. For those of us who have been using RF's for a long time, we have NEVER had such a choice of lenses and bodies.