IMHO, either 2 things are going to happen...
5D4 will come this year without 4K (huge outrage amongst videographers if this happens).
Or
5D4 comes next year or even the year after with 4K.
My reasoning behind number 1, recent price drop of 1DC. No grey market model, straight out of the stable @ $7999 (USD). I don't think they are going to create a separate line that is a Cinema DSLR, going forward.
They will still create Cinema cameras, just not DSLR form factor that is so close to their other EOS cameras.
Going back to price drop, if you look at the Canon 1DC's price history (http://www.canonpricewatch.com/product/03900/Canon-EOS-1D-C-price.html), there is a year where after a price drop it remained constant throughout the year (without any sales). I believe this year its going to remain stable @ $7999 (USD) without any sales too (again, see price history).
I strongly believe that they are going to keep it like this and knowing that if people are waiting for the 5D4 for 4K, they are either going to be upset or they are going to wait.
I am sure that they value their customers, existing and future customers. But I believe that they value current customers more over future ones, because they don't want people to buy something like the 1DC (this year @ $7999) only to be obsolete the next year with the 5D4. People will always think about waiting for the next best thing. But then, you can be waiting forever, not doing anything productive.
They just announced the 5DS/5DSR, only to please the high resolution crowd; they just instilled confidence in Canon fans that they will release future 5D products. Their 5D3 is still selling, what is the hurry to release the 5D4??? People that are waiting can afford to wait, obviously they don't have any real projects on the way, else they would buy our 5D3, right? Or there should be a huge leap in sales in the a7s or gh4, right?
EDITTED TO ADD: If there is either another price drop or another sale (for the 1DC) that happens within the next couple of months, then I would believe that may be they are trying to get rid of inventory and so 5D4 will come with 4K.