You say "What we do know is that the 780ti will replace the GTX 780 at that price point." do we know that?
For all we do know is the 780TI will replace the GTX Titan, the TI suggests its going to be faster than the 780, given that the 780 is less than 10% slower than the Titan I would hazard a guess its a full fat GK110 core closer to Titan's current price point, possibly even $1000 again. with 'IT' getting discontinued.
Didn't Nvidia say "fastest GPU we ever created" ? this is a replacement for the GTX Titan, not the 780, i very much doubt it will be priced to compete with the R9 290X, which looks to be trading blows with the Titan, for that reason also, i think Nvidia are throwing in the biggest gun they have, just to stay ahead even if its only 10%, they can still charge £700 or more for it knowing it will sell like alcohol in an AA clinic.
And then there is this 4K thing, Nvidia are pushing that and they may want a GPU that they can advertise as a "4K specialist" with an appropriate 4K price tag. i guarantee they already have a line of reviewers selected to sing its praises on how awesome and fantastic it is with 4K.
I'd put money on thats what this is, the bigging up of it has already started.