I wrote a mech IG list recently using a platoon (PCS, two infantry squads) and veteran squad for troops, all in chimeras. The warlord was Pask and the rest of the army was tanks
I like vanquishers in today's meta. Pask in a vanq (lascannon and melta sponsons) and an executioner (plasma sponsons) was my HQ. For my heavy slots another vanq and an eradictor with all heavy bolters. Then three wyverns. Wyverns and eradicators seem like great value and whatever people think of vanquishers I think they suit the meta with lots of wave serpents, knights and MCs needing to be killed.