Don't get me wrong, I don't doubt there'll be some kind of new big kit... I doubt that it'll be 2-2 1/2 times the size of the Tyrannofex (although I guess there were those Dominatrix rumours earlier in the year - that would be about right scale wise, since the Domi used to be a bio titan roughly the size of a baneblade).
I mean, there's already not much difference between the size of a Tervigon and a Hierodule
(although the greater bulk of the latter can justify the Monstrous/Gigantic creature difference), so how much bigger can you sensibly go while still classing it as an MC rather than gigantic creature?
(Plus, I've no idea how the hell I would transport anything that sort of size to regular games...)