You can always make new maps, you just have to be patient to actually use them in game. Or change maps with slight variations, without changing tilesets or dimensions.
Be careful that maps always must come with their proper waypoint data (.RMP files).
Fun fact: did you know they had a tileset in mind which was never released? It was called "shack", which would probably be used in combination with "forest", like "barn" is used in combination with "farm". I found a reference to a "shack" tileset in the beta exe.