I've worked out a list based on what I've got between the BaC and BoP boxes. Floating this list over on /r/Warhammer30k got me decent feedback.
-cataphractii Terminator Armour
Tactical Squad (20 man) [mkIII]
Tactical Squad (20 man) [mkIV]
Tactical Support Squad [mk III]
-5x melta guns
Tyrant Siege Terminator Squad
Iron Havoc Support Squad [mk IV]-5x Missile Launcher
I've already started work on the Havocs. I'm keeping my eyes open for good deals on Iron Warriors shoulder pads, and I have some rhino hulls to convert over to Heresy Era vehicles.