Gumpaste or Cold Porcelain?

I've recently been asked to make a non-cake presentation piece.  When I was approached about this project I made certain that the interested party understood that I normally work in cake and edible elements.  So, after talking about what they were looking for and what I could do for them, we decided that what I would create for them would be a styrofoam construction, covered in gumpaste and other sugar pieces.  But then I started thinking this week as some of the construction began, wouldn't cold porcelain be better?

Gumpaste is really great for working structures that need to be solid because it sets up very solidly.  When done in a 50/50 mix with fondant it is even stronger.  But in this case the entire project is meant to be a keep sake and really has no reason to be made of sugar.  I'm thinking this three and-a-half week project will be mostly cold porcelain when possible.   I will not be able to post pictures until this is complete as the whole project is a huge secret.  But I will take pictures as I go so that they can all be posted afterwards.