Sauté pancetta in heavy large skillet over medium heat until crisp. Using slotted spoon, transfer to paper towels. Reduce heat to low, add onions, sprinkle with sugar and sauté until brown and tender, about 25 minutes. Transfer onions to bowl. Add broth, beans and arrowroot to skillet. Simmer until beans are tender, about 5 minutes. Using slotted spoon, transfer beans to onions in bowl. Cook liquid until slightly thickened, about 10 minutes. Add 1/4 cup Marsala and marjoram; return onions and beans to liquid. (Can be prepared 1 day ahead.)
Preheat barbecue (medium-high heat). Brush veal with remaining 2 tablespoons Marsala. Season with salt and pepper. Grill until just medium, approximately 3 minutes per side. Transfer veal to plates.
Meanwhile, simmer sauce 3 minutes. Season to taste with salt and pepper; stir in pancetta. Spoon sauce over veal and serve immediately.
Per serving: calories, 340; fat, 19 g; sodium, 223 mg; cholesterol, 95 mg Nutritional analysis provided by Bon Appétit