I think that Ementaler's tiles (or a less detailed version of my originals) could fit into DodgeS' idea with some appropriate recoloring and deisometrication, as a (layer 4) background. I can post an image of what I mean in a few hours if necessary. I would vote for losing isometricity from Ementaler's over adding it to DodgeS' because isometric tilesets, particularly ones that use the full isometric and not what Disguise calls "Semi-isometric" perspective, are harder to use, take up significantly more tiles, and take more time to make. Also I think that cases like in this thread, where the isometric floor uses the same graphics as the actual wall tile, are easily the least attractive way of making an isometric perspective. It works well in nature tilesets, for instance, because your floor is grass and your wall is dirt or rocks or something and they look distinct and interesting, but I don't feel the tileset gains anything from doing it this way.

ETA: Also I like DodgeS' floor and feel it has some good possibilities for walls that are interesting to look at, especially as it is built on and given more variation.