For the last 6-9 months, Microsoft have been showing a demo of how a user could create a filter on a list place and invoke an action called Edit In Excel. This would open Microsoft Excel with the same records, the user selected in the List Place and allow the user to edit values and post modifications back to Microsoft Dynamics NAV, showing how the user would get a runtime error if he was trying to violate validation logic from NAV.

Freddy Kristiansen has wrote this demo, and has made an posting with the explanation on how he did it. You can find it Here