The last month or so has seen a steady stream to our inbox of EOS R and RF mount information. Some will obviously be wishlists, but some of the information will be accurate.
We've been told on multiple occasions that an RF mount video product of some kind is in development. While only one of the comments mentioned a Cinema EOS camera, a couple of others said it would likely be outside of the Cinema EOS in its first iteration.
Most of the people we have talked to seem to agree that we won't see such a camera until 2020 at the earliest, and not to expect this kind of hardware announcement for NAB in April of 2019. The RF mount needs more native lenses before an RF mount video product makes sense.
That said, I do wonder how many video shooters would appreciate an RF mount video product just to use the RF to EF filter adapters.