It would not make sense for them to release a APS-C camera that is equal to or better than the current FF sensors... but if they did, it would be in the price range of the 1DX.
I doubt APS-C can, at this stage, equal or better FF sensors. But, I bet they can come close. If they can come close then I could see the direction of the 7d2 being the smaller kid brother to the 1dx. I could see a body like that fitting in the range between the 6d and the 5d3. Canon has no reason to make an aps-c in the price range of a 1dx --- then it would be too much direct competion for 2 sports bodies.
If there is another body in the 1dx range my guess is it will be the big MP body, which would be in a totally different league than the 1dx. Incredible res, much improved DR and low ISO performance, and far lower fps. The 1dx would still be valid, only difference to canon is that only those that need what a 1dx would do would buy it, those printing giant landscape prints nad doing high level studio work can buy the big MP monster.