We should add a lifecycle state for Maintenance: the portlet is currently unavailable, but will be placed back into service when it is. Instead of disappearing – as an Expired portlet does – the portlet chrome would still be there (in a tab/column setup), but instead of the portlet itself there would be some sort of "out of service" message.
A textarea for entering a custom message would be awesome, time permitting.
Apparently something like this capability used to be a uPortal feature some time back in the 2.x era.
Plan to add a PORTLET_MANAGER_MAINTENANCE_ACTIVITY.
Taking 4.1.2 off the list of fix versions for the present, pending planning discussion.