What is the significance of calling it a larger EF mount? Does that imply electronic compatibility...as-in you can mount one of these lenses to an EOS body with an adapter and maintain full functionality?
It would be neat to see that, but I agree with most of the sentiment in this thread. Going to be crazy expensive.
My opinion for the mention of the larger mount is the need to add credibility to this noise so the life of the rumor is continued.
There is no real business or technical argument that justifies the development or acquisition of MF capability.
As to the comment of introducing a show stopper....that is a "quote" from unattributed sources that, if true, could mean anything from a magical Foveon sensor to a new logo in the fevered imagination of a sled person.
Sorry, but this seems to be the weakest rumor with the weakest "facts" to support it.