These reports first started in 2014 and showing up in 2016 with seriousness, and some reported even said the system may be launched as soon as 2017, but now the consensus is that this system may have been delayed to 2018 due to issues with the EF mount in a mirrorless form factor. This makes sense, the mount was designed for mirror based SLR/DSLR AF systems, and getting it to work with mirrorless systems is an understandable hurdle. However, there was a pellicle mirror camera designed for the system.
Not to mention the size differences. We don’t know how Canon is planning to implement the EF Mount into a more compact mirrorless chassis, but that alone could possibly be some of the hold up here. Balance and ergonomics have been a big thing with Canon’s DSLR cameras, so it wouldn’t be a surprise if they spent extra time trying to get it right with their full frame mirrorless system.
As far as the rest of the camera goes, it is looking as if we can look for an around the mid-high 30-megapixel mark (so like 35-39MP), with 4K video and an official unveiling most likely at or around Photokina 2018.
It will be interesting to see how this affects the Canon EOS-M line, which has been more or less an experiment by Canon that always seems to be a step behind the other mirrorless companies. Anyway, you can stay up to date with the latest Canon full frame mirrorless rumors over on Mirrorless Rumors, and we will, of course, be updating you with any further developments as they become known to us.