I would suggest seeing if you could find any of the Dust buildings. I've used them a few times - don't have any pictures handy, sadly.
I would also 2nd the Plasticville. Finally, you could also go with more O scale with Ameritowne. They are brick facades, but you can buy the sides, too. The brick is a bit small for 28mm, but they look good. I used several of their buildings in superhero games with the kids using Heroclix and they looked good.