Hi Rebecca,
Unfortunately there isn't an app or page that would match the Track > Release Metrics page exactly. Much of the information presented on the page is also available on the Portfolio > Portfolio item page. For example if you add the "Percent Done by Story Plan Estimate" column you will see the percent done, but if you click on the bar it will break down the number of item total vs the number accepted, and point total vs the points accepted. There are many other columns available that may help as well. I know its not an exact match, but I hope it helps.
You could also post this as a suggestion on CA Agile Central Ideas at http://ideas.rallydev.com/ to garner additional discussion and votes from other CA Agile Central users. Then, share the link to your idea to a relevant discussion post in the CA Agile Central Community () to secure votes and comments for the idea.