Something to consider...
Can vary a terrain's appearance, buy duplicating a terrain & then resize, change angles, etc... change the parameters for the same texture ( or change to another texture altogether) and have both terrains in virtually the same space... or create another terrain that is different physically and overlap, jut out of, rise out of and above, etc....
A low tech technique that I'm a bit fond of, but doing this will increase the scene's poly count and will increase your render times....
Also can use a paint program and "paint" a terrain map to use, and then there's importing a bitmap to use as a terrain.....
Have fun, play and experiment.
best, hewsan