I was inspired by the graphics of Dofus Arena and decided to try and create some similar tiles… Spending half a day fooling around with Fireworks I ended up with this image:

Another half a day later I turned the graphics into an animated terrain generator: http://www.powerupmedia.nl/#/exp080302

The terrain is generated according to three small bitmaps (see top left corner). The first one determines the type of the tile. The second one is like a bumpmap and determines the elevation of eacht tile. The third bitmap determines where objects (plants, rocks, gold, etc.) should be placed.
In the future I might create an editor which can write the bitmaps.

Once I designed more versions of each tile-type (4 or 5 different grass tiles for example) the generator will be able to pick a random version of that tile. This way repetition in the structure should be avoided (at the moment the tiles are just mirrored at random).