Banner Message?

Is there any way to display a banner message on the TC home page/projects page with "message of the day" kind of information?  Specifically, we are planning maintenance in a few weeks, and would like to display a notice of when this maintenance will occur.

I know there is a maintenance banner when you turn on maintenance mode, but we want something that will warn about upcoming maintenance.

Any way to do that besides trying to edit the jsp pages manually?  If that's the case, where would be the best place to insert this message, and in which file?

Is there maybe a plug-in that can be used for this?