I'm also considering going with a Legion Sicaran Battle Tank. They're just damned cool looking. It also doesn't hurt that the Forgeworld sample is painted up as an Iron Warriors tank...
![Legion Sicaran Battle Tank](https://www.forgeworld.co.uk/resources/catalog/product/600x620/99590101336_LEGIONSICARANBATTLETANK3.jpg)
I'll probably keep thinking about it. The other possibility is to just steer clear of the heavy hitters and get a couple of Rapier weapon platforms. I'd probably be looking at the Quad Mortar as it seems to fit the Iron Warriors fluff the closest. Time will tell. I have plenty of time to think about it.
![Space Marine Rapier Quad Mortar](https://www.forgeworld.co.uk/resources/catalog/product/600x620/99550101455_SMRapierQuadMortar01.jpg)