Rank Function

Currently the only way to rank dimensions by metric is to sort them (example: page URL's by Visits). But what about when you want rankings for a certain metric to persist, even after you've sorted by a different metric? (Similar to the Rank function in Excel). This is particularly important in web analysis from a page performance and path optimization perspective as it's possible to create participation/contribution metrics but extremely difficult to track changes in rank leaders over time. The fix for this would be to add a simple rank function in the metric container.