Not even a hint has been given, but I'd imagine it's a fairly safe bet that Fyreslayers will get one - they are new miniatures, after all, but do not yet have their own box. Other possibilities are a bit less obvious, but I'd guess that anything that has reasonably new plastics is fair game.
The rumour seems to specify that the boxes coming out will be larger than the standard ones - so it's also perfectly likely that we will see bigger army boxes for Stormcast, Bloodbound, Sylvaneth, etc.
Me, I'm just holding out hope for a Soulbight box with a pile of shiny new plastic models!