I received a tip that Kipon is working on a new Iberit 18mm tilt-shift lens for Leica M mount. I am not aware of any native tilt-shift solutions for Leica M mount – you need to use an adapter or one of the Canon/Nikon T&S lenses (also with an adapter).
Kipon recently introduced several Handevision Iberit full frame lenses for Leica M mount.