I very much like how the Release Burndown report displays the information within JIRA for communication with my teams and stakeholders.
The problem is that I have the program I have is massive, high priority and has very high visibility. The ability to use the Release Burndown report for the multiple releases in the different projects in the program would be very very useful for clear communication.
I would suggest a similar diagram at the top, with the ability to show the releases/initiatives/epics beneath as story level would be too detailed.
A similar portfolio level Version Report (from JIRA) would also be useful.
Finally... for both of these reports:
These reports are point in time type reports which are useful.
What would be incredibly useful, however, is to include the change in estimated completion sprint over sprint (perhaps for the last three sprints. That way I could very quickly assess if the situation is changing favourably or unfavourably.
If you like I could provide a mock up. All of the basic data is already in JIRA.
At this point I would suggest creating a Suggestion on JAC and include the use case along with the diagram. That will allow the developers working on Portfolio to see this and take the necessary actions. Once you do that please post the link here so the community can vote on the issue to add impact.