Combine graham cracker crumbs, reserving 1/2cup, marshmallow pieces, dates, chopped cherries, half-and-half, and pecans in a large mixing bowl. Mix well.
Spoon mixture onto waxed paper, shaping into a 12- x 3-inch roll. Cover with reserved graham cracker crumbs. Wrap securely in waxed paper, and chill several hours or overnight.
Cut roll into twelve 1-inchthick slices; place each slice on a dessert plate. Dollop with additional whipped cream, and garnish with a cherry.