The Wall of Martyrs individual kits are now up for advance orders to be released on December 1st. There are three box sets coming with these, so that you can mix and match, or expand upon what you already have.
I am glad they did this with this set, as you can now build your lines how you would like, not to mention that we had rumors of parts of it coming out in the next codex as a fortification.
Games Workshop Advance Orders
Wall of Martyrs - Imperial Defence Line $41.25
Wall of Martyrs - Imperial Bunker $33.00
Wall of Martyrs - Imperial Defence Emplacement $29.75