IDW have released the cover for Countdown to Darkness #4, revealing a Klingon as a primary character in the series:
We've seen John Harrison and the Enterprise gang playing with Klingons on Qo'noS in the trailers, so I guess we'll be exploring the background to that element of Star Trek Into Darkness.
Here's the cover without all the titles, as posted by David Messina on his blog, you can also see it pre-colouring there.
And here is an updated version of my mock-up for the omnibus cover. The delta segments on the covers released so far don't actually line up quite right, so I've super-imposed my own over the top, but you get an idea what it will look surely look like: