If what you read on the rumour pages is true, Canon has an interesting camera announcement for filmmakers up its sleeve. The first Cinema EOS with the new RF mount is supposed to be released soon -- for allegedly 4,500 dollars. This would put it in the price range of the C100 Mark II, which was released about five years ago.
For this price, an internal 4K 4:2:2 10bit (ALL-I / IPB) recording in up to 120p is supposed to be available, RAW only for an external recording. So basically what the recently introduced Sony A7S III offers at a similar price.
The Super35 sensor from the C200 is supposed to be installed, in addition there should be internal ND filters, 2x Mini XLR and a recording on CFexpress Type B or SD UHS-II (dual). So far, so standard, on the other hand, the information that the camera should be operated with two LP-E6NH batteries and be smaller than the EOS 1D X Mark III.
The latter is due to the DSLR form factor a slightly oblique comparison, and why two small batteries instead of one larger one? If this information is correct, the camera would have to have a different housing than previous Cinema EOS models.
This would be quite possible, because a patent application from Canon last fall shows a smaller Cinema camera that has a slot for exactly this type of battery. However, only for one and the optics seem to be firmly installed. Therefore, the patent application also contains information about the planned cooling of the sensor, like Newsshooter already explained quite detailed.
What is true about the rumors, time will show, but such a camera sure sounds interesting.