Honestly, I haven't abandoned this project:
Sprayed white, then washed with grey until it looked totally dirty and horrible... now I'm bringing the features out with white again. Not the most exciting painting work, but it's coming along okay.
As a side note, I see the Ion Age are releasing some cool connectors/tunnels to link together all their sci-fi colony hab structures:
Looks pretty amazing, not to mention versatile! More details in their blog post here.