I still think single SD or CF card could cause a bottleneck in the data pipepline. If you do the calculations you'll see that 24MP at 10fps is a higher data rate than the 1DX so I doubt it will actually be that much. It is more likely to be around 23.3MP (like 5D-III) and 9fps, which would still be an improvement on the 7D. Those numbers at least seem to be inline with the capability of the dual-digic5+ architecture as seen in the 1DX.
If you have a 95mbps SD card and the slot/chipset supports full speed 95mbps then single SD slot should be no problem. If an older tech slot/controller on the camera is used then it may be.
i.e. one of these:
You can't really use the number of frames per second or the number of megapixels to argue if the slot is SD or CF without considering the buffer size. Nothing states how many shots before the buffer fills or what the size of the buffer is. Make the buffer bigger and you can live a lot longer with a slower storage card...
If you want to run continuous, assuming 32Mbyte per raw image and 12FPS, you are looking at 384MBytes/sec sustained transfer speed.... that's 32 times the speed of your 95Mbit/sec SC card or 6 times the speed of a 160Mbyte/second Sandisk Extreme Pro CF card. ( Read speed is 160MB/sec, write speed is 65MB/sec). Whatever technology they put in the 7D2 for card slot, it is the buffer size that has the most impact.....
If you assumed a 2 second burst and a buffer big enough to hold 2 seconds at 12FPS:
SD - 25 frames and 64 seconds to clear it
CF - 29 frames and 12 seconds to clear it
Does anyone really think that Canon would make a semi-pro camera that can sit there for over a minute trying to clear the buffer? The smart money is on CF.