Nope, sadly no one with any serious HLSL knowledge has come forward to attempt it, it's also somewhat unclear what the limitations are.
I know Sytner knows and did some stuff, regarding shaders, but mainly for his terrain tool. Shadows are also still a question mark, Uli wanted to give it a shot, but hasn't yet.
If that's what you mean by 'lighting' at least, the only obvious and straight forward tweak is changing the color of a terrains lighting.
Okay thanks, yeah... ironically im going to school for game art and design. I love this game so much and I bet I can contribute to making more mods. Just gotta get more knowledge under my belt.