After yesterday's rehashing of past rumors in a package mimicking new information, EOSHD is reporting the 4K video reports in the EOS “5D” line are untrue.
…..the company believes a 4K 5D Mark IV would completely overshadow the recently released C100 Mark II and so wouldn’t happen, but that Canon LOG would likely go into the camera to allow shot-matching with the XC10.
This sounds completely plausible. I get the feeling that Canon doesn't see a big future in DSLRs for serious video productions and will try to further grow their Super 35 Cinema EOS cameras instead. The XC10 is the odd camera in the strategy, but we'll reserve judgement until we hear from people that have used it in the field.
We can't confirm a “5Dc”, but we can confirm that we were told there would be 3 “5D” cameras in 2015 and that we've already seen 2 of them.
Source: [EOSHD]