[REQ] Layers to EXISTING materials

[Pixero]

I use the layer names to materials script when importing dwg's from Revit and it works fine applying random colors to all layers.
That is fine when you import a new dwg but sometimes (quite often actually) there are changes so you need to import again. Then it would be useful to be able to select what layers should have what existing materials. A bit like TIG's global material changer but not quite and preferable by selecting materials from dropdown menus and layers from another or maybe by automating it even more somehow.
Does something like that already exist?

Oh, and a option not to put materials on backside.