Do you like other religious classical music? My faves in that sub-genre are Requiems. Have you ever heard Berlioz's? Grandiose and awe-inspiring, yet a deeply personal expression of grief and ultimately peace (no, I didn't steal that from the liner notes).
I'm pretty sure I have a CD of the Berlioz (Grande Messe des morts). My tastes run to the romantic, so he's a favorite on other fronts. Brahms's Ein Deutsches Requiem is likewise haunting, but hardly the sort of thing to cheer you up :-)