Hello,
Regrettably, there is no such module available in Kentico up to this date, but you can try the following approaches:
Use a third party
module.
It depends on what kind of banner you want to have.
You can develop your own
webpart for it.
If you want to use banner which content will be changed on the page load, you can use the
random document webpart.
You can also add to the pages flash and/or java script elements.
Best regards,
Boris Pocatko