Heat oven to 350°F. Grease a 9 x 13-inch cake pan and line 6 muffin-tin cups with liners. Prepare both boxes of cake mix according to package directions. Fill cupcake liners 3/4 full and pour remaining batter into cake pan. Bake cupcakes 25 minutes and cake 45 to 50 minutes, or until a toothpick inserted in center comes out clean. Transfer to wire rack and cool 10 minutes, then invert and cool completely.
Carve cake into a bowling pin shape. Use scraps to build up lower part of pin into a rounded shape. Cover pin with vanilla frosting. Attach fruit strips to bowling pin to make bands.
Tint remaining frosting purple with food coloring. Frost cupcakes; dip edges into nonpareils.