Site wide preview function that takes account of the date
The existing preview function shows a page as it will appear when scheduled content goes live. As such it takes no real account of the system calendar.
The idea therefore is to allow the user to alter a calendar offset, such that he or she can see the site as it will appear at some future date. The user would be able to role the calendar forwards to view scheduled changes as time elapses over a period in the future.
The essential difference between this and the preview mode is that it would show the various phases, so for example if I had new content scheduled to go live next week for one week and other content scheduled to go live in two weeks time, I would correctly see how the site would look at any time through these changes.