Small extension to Panels that provides a simple panel pane type called a "Custom header". This functionality was originally developed for a newspaper site with a lot of sections on the Panels-driven front page, where we needed to group panes together under a section header:
If you view that site, the different brown section headers ("ECONOMY", "OPINION", "U.S. POLITICS", "WAR AND ANTIWAR", etc) are provided by this module.
These panel panes only have a few fields: header text, URL (if you want the header to link somewhere) and the access and CSS id and class fields from Panels core itself. The look of the resulting headers can be entirely controlled by CSS, but if you need it, there's also a theme function ("theme_panels_header_pane()") for the output of each header.
Although this functionality originally lived in a site-specific module, I find myself needing something similar on most of the sites where I'm using panels for the front page, so I'm splitting it out into a separate module that can be reused by others. After discussing this with merlinofchaos, he'd rather not commit this functionality into Panels core itself, since he has dreams of "container panes" that could hold other panes. In that case, the pane title for the container pane would act like these panels headers do. However, until that exists, this module is available to fulfill this need...