I currently have a 95% finished environment concept which can be seen here: http://imgur.com/3ZQqyW8. It's of a map in our game development project. The original artist and I are having trouble getting the grass right so we thought hiring multiple people to try it would be a good idea.
I will send you the full layered PSD that currently has no grass texture. All you need to do is do your own design on the grass, whether that be dirt, stone, grass, metal, leaves, etc. We do have a utopian, futuristic world planned, so something very lush and green and carved stone and perfect patterns/architecture is preferred to scattered dirt, random stones, etc.
I can't imagine this takes you longer than an hour. Each half of the map needs to be identical so you actually only need to do half the map, then just duplicate it. But, you do need to plan this out and have detail, I do not want you just adding dirt paths and calling it done. This is a good example of the kind of detail I'm looking for: http://i.kinja-img.com/gawker-media/image/upload/t_original/hzywvhhurs0derfxhnwa.jpg
Our map is a MOBA map, so here are some additional examples: