The new TTartisan 28mm f/5.6 lens for Leica M-mount is now available for sale again after the first batch was already sold out.
The lens is also listed for pre-order at Adorama, Amazon, B&H, AliExpress, and Pergear but I believe the fastest way to get the lens is if you order it directly from the manufacturer's website. Previous coverage of the TTartisan 28mm f/5.6 lens can be found here and here:
A few quick sample photos from the new TTartisan 28mm f/5.6 lens for Leica M-mount
Via LeicaRumors