These are rumors, but come from very good sources.
via an anonymous source on Faeit 212
Adeptus Mechanicus Skitarii
box contains 10 new plastic models. They can be made up as either Skitarii Vanguard, or Skitarii Rangers. Both units contain special and close combat weapon options.
Adeptus Mechanicus Ironstrider
Said to the backbone of the Adeptus Mechanicus Scout forces. It's a dual kit allowing you to make either the Ironstrider Ballistarius -long ranged heavy weapon walker, or the Sydonian Dragoon which is a close combat version.
It comes with a riptide size base and stand just as tall as the Riptide or an Imperial Knight.