Material mapping and interreflection calculation

Hi list,

I have an idea I don't really now 1. If it is feasible 2. If it is, how to apply it...
Allow me to explain:

When it comes to mapping material colors or photograph and textures to a 3D geometry funny things start to happen in certain situations, i.e. a noise pattern used to simulate a fabric will create ambient rays with different colors & intensities depending on the point in the map where they bounce. For accurate illuminance measuring, though, we could get away with the mean reflection / trasmisivity of the surface (as long as the scale of the perturbation is not big enough), so: is there a way to tell RADIANCE to use those mean values for the interreflection calculation and after that just stick the map & texture on the surface for 'slickness' purposes only?
I know one can play with sample interpolation, but still in certain situations big color variations happen. Does this make any sense to any of you?

Thanks,

Ivan Pajares