Unity Skyboxes

I've been fiddling around with a new skybox texture for Wreckless Conduct. As skybox texture creation isn't covered in the Unity manual, I did a hunt around for some tutorials/information.

Flat Images for Skybox (A Unity Answers diagram) and Creating a Skybox discuss the same method but works well if you're using a 2D app like Photoshop. See also this tute from CGTextures.

"As Unity uses a sphere to project the skydome it is best to use Maya or Vue to create the textures for the skybox as the spherical projection is hard to get it right within a photoeditor only." (From the Unity Forums)

I've been told Unity will blow the skybox textures up so high-res images are a good thing.

Here's some old attempts at the skybox: