It depends what prototype they go with.
It seems Nikon have been a bit crafty with the D800 and created a whole different segment (high res).
Now it can release a FF equivalent of a D7000, yet still maintain clear product separation without having to gimp the camera.
Rumoured spec's here
Will Canon give you a FF 7D?
Apart from the body, I think they will.
A low cost FF camera will be a high volume product, so good business decisions here are critical.
The D600 looks like it can compete with the 5Diii at
rumoured half the cost.
When Canon weighs up it's options, I expect them to realise it should not be so concerned about their entry FF stealing sales from the 5Diii. Instead it should be scared of the D600 stealing sales of the 5Diii. The latter is considerably more damaging to Canon.
Also, let's not forget that Canon also has plenty of room to discount the 5Diii to make it more attractive. I think it will have to do that anyway once supply of the D800 can keep up with demand. Although from looking at the past, Canon may try to avoid this considering it has previously tried a little too hard to stop internal product cannibalisation. However with the 5diii they didn't do much gimping, which is why I think it got a big price hike over what people were expecting or what the competition were offering.