Scraping by the skin of my teeth, here's my submission, a high wealth residential building designed to fit a 3x4 lot:
I tried to analyze the art style your game has so far and replicate it as best I can.
The roof is bare as I was hoping to have it cluttered up a little by your ploppable game assets when it gets imported.
The structure butts up against both sides of the 3 unit width so it can look consistent across multiple lots if needed.
It also makes use of the colormask feature for the walls.
Wireframe shown is 2.2k triangles, LOD (not shown) is 98 triangles:
Texture sheets (all 1024^2), diffuse, normal, specular, colormask:
(Apologies for editing my post again after the deadline, I didn't have much time to take decent pictures.)