Hi @johnc,
thanks for passing the link to a pile. Any move in this direction will be really appreciated 
I had a really hard time with FileIO and I had to make a nasty workaround to automate the second instance of Rhino and copy/paste models to achieve desired results. You can read through it - in short, I wanted to export the model in a block with related materials - each time I ended with an incomplete 3dm or huge mess in the material table. Collecting bits and pieces and patching the whole thing with scripting was the only way out to do this.
Ok. I will put a period here to not mix these topics 