Set up your grill for indirect grilling and preheat to medium-high (375° to 400°). In a small bowl, mix the sugar, cinnamon, nutmeg and cloves. Set the rub aside. Make the Caramel "Barbecue Sauce" and set aside.
Cut the ends off the bananas, then cut each banana in half lengthwise through the skins. Leave the skins on. Lightly brush the cut sides of the bananas with the molasses, then sprinkle generously with the sugar rub. Oil the grill grate. Arrange the bananas, skin side down, in the center of the grill over the drip pan away from the heat. Cover and grill until the bananas are tender and beginning to shrink back from the skin, 15 to 20 minutes.
Transfer the bananas to a platter, lining the halves up side by side in a row, so they look like a rack of ribs. Spoon some of the Caramel "Barbecue Sauce" over the bananas and sprinkle the pecans on top. Serve the rest of the caramel sauce on the side.