Wait, there is one for the Pentaka 16 which is a 16mm cinematic camera. That one is a 1.4/50 but I doubt the image circle is large enough for 35mm.
If you want to adapt to Canon I suggest getting lenses in Exa mount. They are plentiful, relatively cheap and of good quality.
Exaktas were the standard for quite a while, M42 only became popular when all the digital people discovered how good the old optics are. Cheap as well, at least compared to the optics intended for the systems.