Something secret coming soon from Hasbro as a Toy that relates to the Dark Cybertron story, that even amazed IDW... Rung came to mind, as the "well known premise from FFOD".
But then, I haven't been reading the story as the issues have come out, so could be any number of IDW characters.

From Editor John Barber...
I think that’s a big moment for us—and there’s this amazing thing happening near the end of “Dark Cybertron” that I couldn’t believe it was going to make the jump to the toys. But I can’t talk about it yet, which is a lame answer but it’s really a fun twist on a well-known premise. It was something that originated—I think, if I remember right—with Mark Weber on Transformers brand team, and More Than Meets The Eye writer James Roberts and I couldn’t believe it was an idea on the table, let alone that it would be reflected in the toys. Sorry to have to be really vague about it.