Yep..and it seems you´re right on the money with that. In an recent con interview Moffat basically says "Whoever thinks that the 3D special is going to be the only thing is nuts".
We know it's not the only thing. There's AAIT&S, a Culture Show retrospective, another Official Convention etc.
What there won't be are any more episodes of the TV series beyond the eight that are in the can, plus Anniversary & Xmas Specials.