The Ribbon component allows you to author Text, and Button subcomponents over a background.  It includes style system variants for background colors, as well as one for a transparency overlay which lets the Ribbon overlay the component that follows it in the parsys.

The Ribbon also has a Shared Property dialog which lets you globally author an authenticated user welcome message. The users name is added to the end of the message. When this option is enabled in the dialog, the Ribbon is only shown when the user is logged into the site.