If I manage a Hudson server and clicks on the "Prepare to shutdown" there should
be a note on the front page stating that the build server is going to shutdown.
Sometimes the build server cant shutdown directly because of a build that takes
20 mins, then it would be nice with a note on the front page.

Ive seen when a job is in the queue, it will display a text that the server is
shutting down. But if there are no jobs in the queue, then there's no text
telling this.