Have a "Deliver by" date option in Inventory Requests

Our FACS department will be ordering food for classroom use next school year. But they don't always have time to enter a request the same day (or the day before) they need it. Give them the ability to put a "deliver by" date on their inventory requests would give us the request at their convince, but allow us to easily see when they want it delivered by, so we don't fill the order too quickly. I've also got need for this for our summer custodial orders, and orders in regards to events happening.