Amazon Japan lists the 6D won't be available for deliver until December 31, which of course is aka for "pretty much next year". By then the there would be Mark3 deals so good that you'd think twice for paying "slightly less" for such a camera!
We can assume the sensor tech is the same as the Mark3, just that it has some pixels shaven off, if there are some more 2,799 deals to expect, then that's a $700 difference for the 1DX level AF, faster FPS, better video capabilities (probably),
full metal body, and SD + CF slot.