This is part of my RTP2 (RTP - Relief Terrain Pack) release on AssetStore, but as a showcase might be interesting for people who deal with terrains. As far as I know this is new approach to making such terrain landscapes.
Here is also working demo available from screenshot is taken.
Note that terrain is shaded with ParallaxOcclusionMapping techniques (with self-shadowing). Terrain replacement shader can be also used in triplanar mode w/o parallax effects).
For more info one might visit this threads:
http://forum.unity3d.com/threads/161235-RTP-Relief-Terrain-Pack-with-geometry-blend-on-AssetStore
http://forum.unity3d.com/threads/171394-RTP-Relief-Terrain-Pack-v.-2-features-tour
BTW - it works quite well on my nVidia GT240 and I’m curious how does it work on your machines.