D Major would be wonderful, as it would be a good key for cello. Some great cello renditions on you tube(Song to the Moon: Hauser playing) is one.
Dana: Hi, Anonymous. Are you saying that there is ALREADY a D version available? Or just that it really sounds good on cello? It's so time-consuming to prepare a setting, especially with a long piece like this one, that I wouldn't attempt it if there are already versions out there.