The main problem with storytelling in singarounds is one of duration; most people go to singarounds to sing & listen to folk songs - to drink beer and join in the choruses - so concentrations are attuned to a certain level of attentiveness, so keep 'em short & snappy and it shouldn't be a problem. There's a sort of unwritten law that states whilst it's fine to do folk songs in the context of storytelling, the opposite isn't always possible...