I have a mix tape made by a friend that has a version of this on it, sung by several (three or four) men's voices in harmony, with a fugue on the second half of each verse. It's gorgeous, but I have no idea who the group was or when or where it was recorded. I'd be happy to copy the tape for you if that would be useful, and I'd be even more interested in knowing who the singers are if anyone has heard a version like mine!