Wired up a Half-Lambertian shader. It's a nice technique for simulation slight subsurface light scattering or very rough objects where light energy would be transmitted from it's hit location to nearby matter. Nice soft fall-off made famous in this Valve paper.
I've uploaded a preset for this material. Note that this material uses a vector share node (I've commented it) to calculate shading; not a light.
Derek Jenson - 3d Artist