My alma mater's theatre department had a dinner theatre each summer untill last summer (the man who directed it retired from the school and no one else has the guts to take on such a project!) and they did Smoke on the Mountain one year and Sander's Family Christmas the next. While they didn't have people QUITE as musicaly talented in the cast they did have an extra part they made up with about two lines and a lot of piano playing for my roomie Chris who is a wonderful pianist. I saw the second show and it was very funny, they even had worked in audience participation.

That school has a wonderful theatre department, I must say. And Mr. Quave was a wonderful director.