What taz explains about the layers parameter and component is exactly
what i visualized that didn't seem to require a big change in how
grasshopper works, just another component. Add rhino layers as another
type of object to be able to link from the rhino model just as curves,
points, etc. The next best thing would be to link materials, and be
able to change some of it's basic properties through grasshopper. I've
read that the main users of grasshopper are architects. Architecture
is not only geometry, but also texture, light and color. Make that
parametric too, please ;)