Did someone say robots?
I think Cygnar is too smooth for an Imperial army.
Models by Kotobukiya:
ARMORED CORE 1/72 GA GAN01 SUNSHINE
Armored Core V Vengeance and Agni
Frame Arms Kagutsuchi
I think these all give a gritter feeling than most mecha. Forbidden Gundam is the only hunchback like model, but it's pretty dorky. Votoms are also an option.