A recently published patent application from Canon reveals the development of new 50mm f/1.4 and 35mm f/1.4 lenses, which use similar optical formulas. We know the new EF 35mm f/1.4L II USM lens is due any day now but a 50mm f/1.4 lens hasn’t really been on the radar even though the current EF 50mm f/1.4 USM lens is getting quite old.
The close focus distance of 300mm on the 35mm lens matches up pretty close to the rumored 280mm close focus distance on the coming 35mm f/1.4L.
The 50mm f/1.4 is specified to have a 450mm close focus distance and be slightly shorter overall than the 35mm f/1.4 in the same patent application.
This application was filed with the USPTO on January 20, 2015 and published on July 23, 2015. You can read it for yourself here.