Of course we're all speculating to some degree, but from reading the description given here, it sounds like it will be a relatively small sensor camera (1" or less) because it will have a fixed lens and will also possibly be announced at CES so more of a prosumer/consumer camera. I took the statement "it will have similar ergonomics to the EOS C100" as meaning the body will look similar to the C100 along with a similar button layout and a top handle with XLRs. I think it would be awesome if it has a sensor that's as large as the C100's and hopefully it will, but to me it sounds like it will have a similar shape to the C100 but not necessarily similar sensor.To me the biggest giveaway is the name. XC10 sounds like its basically the in-between line of the XA series (XA10, 15, etc) and the C-line. So, maybe it'll have a slightly larger sensor (maybe 1" to the XA's 1/2.84") but a lesser zoom range. Which actually would make for a great event/interview camera for my work.
I love the XA line, so, anything they can do to improve that is a win in my book