Interesting post and argument for wearing of black vestments on All Soul's Day over here at the New Liturgical Movement. I, for one, wouldn't be bothered by seeing black vestments at Mass. Personally, my closet is full of black clothes and combinations there of, so... why not?
Of course, I'm just a lay person sitting in the pews. I'm not a depressive, but I've always liked the "slimming" nature of black. Heh.