@
What I meant by Edges are not the edges of the mesh. I meant the edgaes of the map. ie The map (assuming it is rectangular) will have 4 edges. And if we dont have a depth for our terrain modules, the players will immediately notice that they are standing on paper. So we either make sure the users wont see the edges of the map clearly and create another set of tiles with extra faces to be used at edges.
About models.
Have you guys looked at turbosquid.com They have a nice collection of models with varying poly count and different pricing. They even have some free stuff.
are some of the models that we might be able to use: