I did an arrangement of "Sun and Moon" from Miss Saigon for a friend's wedding; it was for violin, viola, and cello, but I'm sure it would sound lovely with piano and cello. (I also did a mashup of "Without You" and "I'll Cover You" from Rent for that same wedding, but that was for piano, violin, viola, cello, and three female voices. Just throwing it out there, in case you want to take a listen!)