In a small microwave-safe bowl, heat candy coating and shortening, uncovered, at 30% power for 3-4 minutes or until melted, stirring every 30 seconds. For eyes, coat the large cookies with candy coating; place a miniature cookie in the center of each for pupil. Place on waxed paper to harden.
With a sharp knife, cut a thin slice from bottom of watermelon so it sits flat. Beginning above center at one end of melon, lightly score a horizontal cutting line (leaving a fourth of the opposite end unmarked). Repeat on other side of melon.
With a long sharp knife, make a vertical cut from top of melon to end of cutting marks. Cut along the cutting mark, making sure to cut all the way through. Gently pull off cut section; cut a thin slice for a spoiler. Trim spoiler piece to fit smoothly against the end of the melon; attach with three toothpicks.
Remove fruit from the cut section and from inside the melon; cut into balls or cubes and set aside.
Using a sharp razor blade, carefully carve a smile in the front of the watermelon; carve a number in the side and add other designs if desired. For wheels, attach lemon and lime slices to each side of melon with toothpicks. Attach cookie eyes with toothpicks.
In a large bowl, combine the cantaloupe, honeydew and reserved watermelon. Spoon into car.