I'm not sure what you are basing that on. This could very well be the 1D Xs.
Speculation. It's fun. Sure, it could be called 1D Xs. But again, I don't think so, especially if it's going to be a non-integrated grip body, which is my preferred option. In the other case, why not? But unlikely. Remember Canon introduced the "X" to represent the merging (crossing) of the 1D and 1Ds lines, and now what? Splitting in two the 1 series again and keeping the X, though both FF?
I have always understood that what they meant with "merging of the 1D and 1Ds" meant the actual merging of 1D IV and 1Ds III cameras not the actual 1D and 1Ds "lines" meaning that they forever excluded the possibility of a high speed 1D and a big megapixel 1D. Watch the official announcements again after you read this post, they didn't say exactly what you thought.
Another take that i think could be possible is that they meant that the 1D and 1Ds lines merge in to a 1DX which does not exclude a 1DXs line.
Big companies sometimes say things that is useful for marketing but customers take them too seriously.
From Canon: “The EOS-1D X represents the re-invention of the EOS-1Ds and EOS-1D series
" ... (Yuichi Ishizuka, executive vice president and general manager, Imaging Technologies and Communications Group, Canon U.S.A.).
Series, lines... the meaning is clear. Of course, 1D IV and 1Ds III cameras were representative of both series at that time, can you imagine Canon stating that they were merging the 1D, 1DII, 1DIIn, 1DIII, 1DIV and 1Ds, 1DsII and 1DsIII cameras? Don't look too much inside words, the meaning is clear. And marketing paths for the next 5-6 years, maybe longer, were already set by Canon at that time, so it's not a matter of Canon saying "things useful for marketing but customers take them too seriously".
Anyway, I used the words "possibility", "maybe", "could", "unlikely". You'll never hear from me statements of certainty about things not already established. I'm speculating, but I'm trying to use common sense when doing so.
Apart from this, there are other reasons for not going for an integrated grip body for hi-MP cam. Some of them have already been reported by others in this thread. Another one, never really being considered, is that both Canon and Nikon have their (relatively) low-res, high-speed cams embodied by big integrated grip bodies. Those cams are primarily (but of course not exclusively) intended for high speed- high ISO- low light-oriented photography. As Neuro once said, even his P&S takes beautiful photos when plenty of light is available. When we look at stunning high resolution images, or at images taken to test a body and/or a lens, these are taken on sturdy tripods, with mirror lockup and low ISOs. What would be the point of shooting handheld, low light, a 12 fps burst with a 36-45 MP camera (assuming such a camera could exist) if doing so you'll not gain better resolution over a 10-12 MP one due to noise, camera shake and vibration introduced by mirror and shutter? Sure, a photographer sporting a BIG cam looks cool, more macho, sweating manliness from every pore, but if he's using handheld a 45 MP camera @ 12 fps and 12800 ISO (again assuming such a camera existed!) he's also a fool (or the Manufacturer that makes such a camera).
So, let me say again that I think
the next Canon bigMP cam is more likely
to be a non-integrated grip body. And I really hope so. How can you be so sure to say that it will be
in a 1D body?