As a young person in 1995, I don't think I'll ever see a more glorious production than the "Showboat" at the Gershwin. Rebecca Luker, Lonette McKee, John McMartin and the wonderful Elaine Stritch...so huge! That production was so grand they had (probably) every single person in the cast onstage at times, way out on both sides of the proscenium. One of my youngest theater experiences that I'll always remember.
As for today, with all the awareness of old themed storytelling, stereotypes and all inclusive/colorblind casting, I think it would be very challenging, but not impossible...
I Can Has Cheezburger With This?