Into large bowl, measure all-purpose flour, whole-wheat flour, brown sugar, margarine or butter, honey, vanilla extract, baking powder, salt, and eggs. With mixer at low speed, beat ingredients until well blended (mixture may look crumbly), occasionally scraping bowl with rubber spatula. Shape dough into a 1-inch-thick rectangle. Wrap dough with plastic wrap and refrigerate 1 hour or until firm enough to handle. (Or, place dough in freezer 30 minutes.) While dough is chilling, prepare fruit filling: From orange, grate 1/2 teaspoon peel and squeeze 1/2 cup juice. In 2-quart saucepan over high heat, heat orange peel and juice, prunes, apricots, and orange marmalade to boiling; reduce heat to medium-low and simmer 5 to 7 minutes, stirring occasionally, until orange juice is absorbed and fruit is tender. Allow fruit mixture to cool to room temperature. Preheat oven to 350ºF. Cut chilled dough crosswise in half. On well-floured 20-inch-long sheet of waxed paper, roll half of dough into 18" by 5" rectangle, keeping remaining dough refrigerated. With spoon, place half of fruit filling lengthwise down center of dough in 2-inch-wide strip, leaving 1 1/2-inch space at each end. Starting at an 18-inch side, roll dough tightly around fruit strip to form a log. Press seam and ends to seal. Place log diagonally, with seam side down, on ungreased large cookie sheet. With pastry brush, brush away any excess flour on log. Bake cookie log 25 to 30 minutes until lightly browned; cool on cookie sheet on wire rack. Repeat with remaining dough and filling. When cold, slice cookie logs into 1/2-inch-thick slices.