it's worth a note that the 'low end' 1D X camera has a street price of around $7K
the 1D C doesn't appear to be available yet
One issue with DSLR cameras is that they are limited to shooting 29 min 59 seconds of video because if they could shoot 30 min of video they are classified as video cameras, which apparently costs a lot (import duties, patent fees, etc)
from a 10 min google search, it appears that the biggest difference between the 1DX at $7K and the 1DC with street prices of $11K is this 30 minute barrier.
the software on the 1DC also will record 4K video, but when it's doing so it's still only using a fraction of the camera sensor (these are both -only- 18MP cameras, and 4K video uses somewhere around 8MP)
so it does seem to be that the difference between the two (and the almost doubling in price) is just the software.