Put the greens, fennel, radicchio, and pear in a large bowl and toss with about 3 spoonfuls of vinaigrette per person. Pile the dressed greens on large dinner plates. Divide and sprinkle evenly the gorgonzola, pecans, and bacon or prosciutto. If using bacon or prosciutto, place evenly between the salads, sprinkling each element around on the greens. Finish with a grinding of fresh black pepper.