http://www.newvegasnexus.com/downloads/file.php?id=35497#fileanchor
I added a custom skydome, adjusted the exterior lighting, and recolored some landscape textures, with the aim of improving the atmosphere of the Mojave Wasteland.
So far, it only modifies the NVWastelandClear weather and imagespaces, but once I've progressed a bit further in the game, I'll add variations for Hoover Dam, the Strip, and so on.