I've made some progress on my modular Imperial city. I still need to add more colour and detail, but here's what I've got so far:
With the building modules removed, you can see the road layout:
There are pieces of plasticard in the slots to elevate the building modules. This gives the effect of a slightly elevated pavement. The buildings represent three generations of Epic: the original foam buildings from the Adeptus Titanicus boxed set, the ruined buildings sprues from Epic 40,000 and the later Forgeworld Epic buildings:
You can also see a building from Gateshead Gaming, and the previously mentioned Kibri church, which is the centerpiece:
I've also created some ruined buildings, which could be used to replace buildings destroyed during the game:
The roads are arranged so that another board can be slotted in on either of two sides (assuming S6 starts selling the road system again, or I'm able to find suitable replacements). The other two sides will have a reinforced defensive wall from [url=http://www.gamecraftminiatures.com/]GameCraft Miniatures.
As others have said the layout and making the building interchangable with ruined ones is a cool idea 
