Well, back in the day, it wasn't uncommon to see musicals with extended ballet sequences used for storytelling purposes. Off the top of my head, Oklahoma and Carousel both have sequences like this. I couldn't tell you exactly how long any of them are, but many of them definitely lasted at LEAST 10 minutes. More likely around 15 minutes, and I wouldn't be surprised if some of them lasted more like 20-25 minutes.
EDIT: Regarding Oklahoma and Carousel, I looked into it a bit. It probably varies from production to production, but this record of the original Agnes de Mille choreography in Carousel clocks the ballet in at 12:26. And in the film version of Oklahoma, the Dream Ballet lasts just under 15 minutes
Updated On: 5/24/20 at 03:27 PM