I made simple script ( I am python rookie ) for changing color for object in selected material - it changes color in viewport to RED.
It changes colour for every FACE of every object that has attached this material name. This is what I need
Currently I do not know how to build a additional panel in Materials to select colour by Color Selector.
I will try to find out how to create it.
Now you can run it from text editor:
import bpy
print (bpy.context.object.active_material.name)
bpy.data.materials[ bpy.context.object.active_material.name ].diffuse_color=(1,0,0)