Larger sensor than 24x36 would be nice.

I have previously thought about this. I think that at some point FX/FF will become such a commodity that market leaders will have no options but to think out of box.

In my opinion, migration to larger sensor size should not be difficult, just like DX and CX were no problem. Suppose Nikon wants to introduce a larger sensor with a new mount; all they have to do is to launch the new line with a couple of new lenses and provide an adapter to use the current lens line-up with full AF (should be no problem with new G lenses as everything is electronic). Of course this will require a bit of engineering to reduce the flange distance while supporting a bigger focusing circle. However I think it can be done. Nikon already has that flange distance as the industry's highest so there is room to shorten it.

I personally think that Canon may not even need to change its mount and may be able to accommodate 1.1x/1.2x sensor in the same mount.