Trunk will be able to sync your Faire listings to be a stock level of 0. Once it's at 0, it will no longer be for sale on Faire.
Unfortunately, Faire still does not enable you to specify overselling on specific listings but they're aware of this highly requested feature and are working on it. In the meantime, you can give any listing you'd like to oversell with a different SKU on Faire so that it doesn't sync with the rest of your listings and then adjust them to a high enough stock level (e.g. 999).