Actually, I've got a nice unfinished map of a building that suits this map really well. I'm not sure if it's on my current computer or my work laptop. If I find it, I'll edit this post and add a few screenshots. I probably won't go and take this map, but I can work on it with you if you want.
EDIT: Alright, so I can't find the map. When I have time I'm going to make a quick version of the building right now and I'll post screenshots for you to see.