Actually this is might be useful for someone. You can modulate players color, weapon, viewmodel.
But, one thing you need to know, the model should be with specific flag to make this work even in dark areas, where light is not exists. Without model editing, this will only work where the skybox illuminates the surface of the map.
So, you can decompile model and add into .qc file line with:
$flags 1024
Example of .qc file after editing:
Spoiler
Code:
$modelname "v_usp.mdl"
$cd ".\"
$cdtexture ".\"
$scale 1.0
$cliptotextures
//This flag points to force light_environment even in dark areas.
$flags 1024
This flag forces lights the model directly from light_environment, no matter where it is in the map.
Also this flag makes model always with maximum light level (lambert).