In the above video, Carl Zeiss representative confirmed the company's plans for new high-end 85mm and a wide angle f/1.4 lenses similar to the Distagon T* 1,4/55 (fast forward to the 1:15 mark). This is how the new product line was described few months ago:
"This is about lenses for full-frame (36x24mm) SLR cameras with manual focusing capability. This family of lenses is geared towards delivering uncompromising image quality for demanding users. The lenses are perfect for high-resolution, full-format digital cameras with more than 30 megapixels such as D800. The combined performance approaches that of medium format systems. If you shoot with the largest aperture, cameras with smaller number of pixels also benefit from much better image contrast."
Here is another related video interview with Carl Zeiss:
All other things being equal you can potentially decrease the size of a lens by 20-30 percent when going from Full Frame to APS-C and about 30-40 percent when moving to micro 4/3 – but this really depends on the type of lens.
The point of developing the new Carl Zeiss 55mm f/1.4 is to bring unprecedented performance in open apertures. The lens design is actually made of a combination of two different lenses and is a new, first of its kind for a 50mm lens.
The new 82mm front element was designed to produce sharpness across the entire frame.
Don't expect any AF capable lenses from Zeiss in the foreseeable future for Canon/Nikon.
Zeiss can add a stabilizer to manual focus lenses but this will degrade the optical quality of the lens to a degree (it will require some freedom of movement from the optical elements) and so not something Zeiss plans to do anytime soon.
Zeiss highly recommends that you use a focusing screen when using a MF lenses – this is because the conventional focusing screen of digital cameras isn't ideal for manual focus (we can surly attest to that).
Our final question had to do with a hypothetical size of a 50-100mm f/2 lens compared to the more conventional 70-200mm f/2.8. The answer – we are looking into a heavier and larger design and not something most people would like to carry or pay for…