out-of-stock, pre-order, back-ordered
This fits somewhere between resource and intent, thinking about it after looking at basic stock/inventory management in SpreeCommerce (used by Open Food Network)
- http://guides.spreecommerce.org/developer/inventory.html
- http://guides.spreecommerce.org/user/configuring_inventory.html
- http://guides.spreecommerce.org/user/creating_products.html#stock-management
- http://guides.spreecommerce.org/api/stock_items.html
Currently VF could handle 'out-of-stock' with resource which has quantity: 0 I guess planned increment and decrement events could help with supporting back-ordered resources and pre-orders.