Finally, after 2 weeks of patient waiting – here it is: A Sony (made by Canon) 12,5-75mm 1:1,8 c-mount lens. Unfortunately no adapter yet. Will post sample photos as soon as I get one.
Well what can I say - I have mixed feelings about the result. Zoom does not really work with this kind of setup - the usable range is between 40-75mm. On the other hand - 12,5mm is usable too, but you will not be able to zoom in to the higher values as some heavy distortion appears.
Sample photo taken open (1,8).
And a 100% crop of the above image: