Contact Dean Rishel at deanrishel(a)gmail.com. He has arranged O Holy Night for chorus and tenor solo that was a real crowd pleaser when we performed it last year. It's lush and romantic, using both the original first French stanza and the better-known English "translation" -- and a rousing ending. You'll need an excellent tenor, however: we hired a young professional who contributed variously to the concert (Dean also arranged "Ave Maria" for chorus and tenor.) This arrangement is made to order!

I have an arrangement that's been used that way before. Happy to send you a PDF. If you'd like me to -- e-mail me off list at MLMmusic AT gmail.

Craig Courtney's arrangement doesn't have a "big finish", but is my favorite (Beckenhorst).  He also has an arrangement of Silent Night with audience participation.  Paired together they are called "Carols of the Night" w/ optional strings and never cease to be a crowd pleaser.

John W Peterson wrote a Christmas cantata back in the 1970s or so, called 'Carol of Christmas.' The final number is a great arangement of 'O Holy Night' for soprano solo and SATB chorus; we've sung the whole cantata several times, always appreciated.

I have an arrangement that is currently being used by several choral ensembles as their annual concert closer. It superimposes the solo over a collection of familiar carols. The choir members request that they sing it every year, and the audience loves it too. Just before the end it has a huge climax! Let me know if you would like a perusal copy and/or a recording. I also created an orchestral accompaniment for the arrangement which was premiered this past December.

I just love John Rutter's arrangement: https://www.youtube.com/watch?v=q5n6X9sUznI