I thought I'd pass on this wave, but after seeing these pics, I was obviously trying to fool myself. After seeing that Mojo, I really want to try to use that torso for an updated Blob.
http://io9.gizmodo.com/playmobils-new-ghostbusters-toys-are-so-great-youll-wis-1791389754
Ecto-1 is $45 and the firehouse is $70, according to this release.
The Mega Blocks Call of Duty and Halo vehicle sets work well with minimates. Most are in scale with them, just have to modify handles on certain ones, like motorcycles and the like.
Have you looked at the Mega Bloks Call of Duty: Zombie kits? They have some nice looking pieces that include a barn, prison interior and a few other small pieces.