The Canon Cinema EOS C500 has probably been the biggest bust in the Cinema EOS lineup by most accounts. While it was the first 4K cinema EOS camera video specific camera, it was deemed overpriced when compared to the competition and and people were more interested in using the highly successful Cinema EOS C300 and its 4K follow-up the C300 Mark II.
We're told that Canon is working on a follow-up to the C500 and that it will become the highest resolution video camera in the lineup. The Cinema EOS C700 has a 4.5K sensor, so we suspect it will match or slightly exceed that resolution. We've tried to find out if 6K is an option, but we were unable to.
Canon going to 6K with a Cinema EOS camera at this time doesn't seem very Canon-esque, but maybe they'll change the way they do things going forward.
The very large price drop on the C300 Mark II down to $9999 may be a clue that we'll have a new camera priced around $15,000 in the coming months.
Canon has shown an 8K Cinema EOS prototype, but I think it's safe to say we're more than a year away from seeing an 8K product from Canon.
The last three paragraphs are opinions of ours, and we hope we're wrong and Canon pushes the boundaries a bit.