They could make a mini 1Dx, thow FF in it and charge $4/$4,500 making it basically a beefed up 5dm3 but designed for sports with 8/10fps. Also allow the Grip attachment to use a 1d series battery for higher voltage output speeding up the focus system like a 1D, they could charge $600 for the grip then. They could always keep the 1dx tracking and face detection out like on the 5dm3. A 6D would however need to be under a 5dm3 so maybe this camera i mention should be a 3D or at least from a number level being 1 the highest level Canon camera and 5D second highest, maybe put something between them. I know this has prob been discussed and i did think the next 7d should be APS-H but this is something else entirely. The market needs this kind of camera. Canon should be in the process of fulfilling something like this i would think. Who cares if it takes some of the share from the 1dx, you want the premium camera you still get the 1dx. This type of camera would be the first to have the power of a 1d series camera by making the grip the extra source for its kick! Then for the wedding photog's like myself we can get by without that grip for weddings but when we need to shoot sports like i do then the grip makes sense to have. So at like $5100 people will struggle with the features and price over the 1dx. From a marketing standpoint people always want the middle package like wedding packages. They can't afford top but they don't want to go cheap either so this like how apple also prices and puts features in their products to force the difficulty it is pure genius to do so.
Sorry if i seem scatter brained its almost 4am lol.