Whisk first 6 ingredients in medium bowl to blend. Add fish and refrigerate at least 1 and up to 4 hours. Preheat barbecue (medium heat) or preheat broiler. Drain fish, reserving marinade. Thread fish on skewers alternately with onions, green and bell peppers and mushrooms. Arrange skewers on grill. Grill until swordfish is just cooked through, brushing skewers frequently with marinade, about 5 minutes.