The previously rumored 7Artisans 28mm f/5.6 lens for Leica M-mount will be officially announced on May 6th with a price tag of $299 - the same price as the TTartisan 28mm f/5.6 lens. Check the official 7artisans website for updates.
More pictures and technical spcifications of the new 7Artisans 28mm f/5.6 lens: