Inventory levels over time.

How can we run a report that shows inventory (or available to purchase) in the future based on pending purchase orders and pending sales orders? It is kind of like demand planning, but we want to look at levels based on actual orders we have booked, not forecasts.

For example we have current inventory of our widget of 150 pieces, and a purchase order for 500 more pieces that is expected to be received on February 1. Between now and January 30 we have orders booked for 140 widgets. If you look between now and February 20th we have orders for 510 widgets.

Is there a report that will show how inventory levels will fluctuate over this time period based on what we already have booked and what inventory we have coming in? Basically we want to answer this question: "We just got an order for 120 widgets that needs to ship on February 5th. Can we fulfill it?".