Take a look at the current issue of Camera Lens News, a news letter from zeiss: http://www.zeiss.de/C12567A8003B8B6F...e/CLN_20en.pdf
They state that the new ZM lenses have resolved 400lp/mm on Gigabitfilm.

Gigabitfilm has published the quote from a Zeiss letter on their German website, telling that Gigabitfilm has rendered the maximum resolution of their 320lp/mm test chart so well, that they assume even more potential: http://gigabitfilm.de/html/deutsch/a...elles_main.htm

I guess Zeiss is currently developing a new Resolution Test Chart ;-)