Here's another example. http://ericchadwick.com/img/mmo_worldbuilding.html#volcanicbeach It was done for a custom engine, but certainly the same ideas could be replicated in other game engines. One of our graphics programmers wrote the sky system, which rendered four layers of meshes in one pass. I could only use one light…
Does the playable area look like Minecraft? You might want to make the skybox art match that style, using block-based cloud fx. Anyhow, I would approach it by making a 3d sky scene and placing the camera at a high altitude. For example (created by someone else in Vue):…