This would be very helpful. It would be great if the message could be deactivated via an action. I.E. display this message until user 1234 performs action 2345 (such as downloads a report that took a long time generate in the background) or display it until user 1234 clicks "remove" (which would be a lot easier to implement and would likely be good enough).
Of course for things such a letting people know a scheduled downtime is coming one would not want the user to be able to remove the message.
