This was one of the most unique armies I have ever made. A few years ago, Marty and I decided to do the WFB team tournament at Adepticon.
He had already made a sizeable Fantasy Dwarf army themed after the Iron Brigade. He sculpted thier very unique hats, made specific unit flags, and so on.
We thought that it might be fun to do a crazy allied army set of Dwarves and Chaos Dwarfs.
The concept was that as the two enemies fought constantly against each other, many other races had infested their territories. They were both pushed to Appomattox Court House, where the Wretched Alliance of Appomattox was formed.
The 'Union' side would provide more pure firepower, while the 'Confederate', or Chaos Dwarfs, would dabble in magic!
I have a number of posts on the construction of this army, including posts showing how these dwarves were converted...