I visited the Loon Lake Toolworks website for the first time in a while today and saw that they sell a kit that will turn a Stanley #50 into a kerfing plane. I've never wanted to own, let alone build, a kerfing plane, but this is more than a little tempting.
loonlaketoolworks.com

Kerfing Plane Kit for Stanley No 50 Light Plough Plane
After much testing and redesign to improve functionality and reduce cost, the Loon Lake Tool Works Kerfing Plane Kit for the Stanley No 50 Light Plough Plane is ready! The three components in the kit will convert nearly any Stanley No 50 into a kerfing plane used to prepare lumber for resawing...
