I stumbled across this during my travels around the web and thought I'd share it here, especially after reading the comments about a 650b conversion in recent posts.
It's a video from Paul Components about their cantilever and V-brake conversion parts to let you adjust the brake pad location on a 26" fork to run 26", 650b, or 700c wheels, assuming adequate clearance of your particular fork and tire choice.
https://vimeo.com/158260982