Basically the title states the obvious question... I have this beautiful idea, but it requires two different materials silver for one object and gold for the other.
The two parts would have to be separate, to be assembled by the customer (or you would have to order the parts for yourself, assemble and then sell through other channels). There used to be a tool in the "labs" section to create a "buy the set" button that would add all the required models to the customer's cart, but sadly it got broken by one of the site changes a few months ago.
I saw machines for printing in two plastics (or rubber+plastic), but no see it on SW and other similar services.