I haven't seen an example of this but is it possible to add a splash screen to any of the story maps? We're self-hosting our story maps.
See also: Is there a story map template that allows a Splash page?
Since the story map is based on dojo you could create a splash once the following event is run (map journal as an example):
Here's an example of a Story Map Journal with a splash/cover page added via customization. It was created by Esri Colombia: http://geoapps.esri.co/salgar/
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