Does anybody know if it's possible to display the current stock levels (products availability, quantity on hand) through the customer portal? If yes, how to do it?

In our warehouse we are storing and managing goods which are owned by other companies - we would like to give them an option to view the current stock quantities on demand through the portal (so they can check immediately what's in the warehouse, without asking us to check it through phone/mail), but we don't want to give them access to the backend.