1In small bowl, mix oil, vinegar, rosemary, salt and pepper with whisk; set aside.
2In resealable food-storage plastic bag, place beef, mushrooms, bell peppers and onions. Pour marinade over beef and vegetables. Seal bag; turn several times to coat. Refrigerate, turning occasionally, at least 3 hours but no longer than 8 hours to marinate.
3Heat gas or charcoal grill. Remove beef and vegetables from marinade; reserve marinade. On each of 8 (10- to 12-inch metal skewers) alternately thread beef, mushrooms, bell peppers, onions and tomatoes. Brush with reserved marinade.
4Place kabobs on grill over medium heat. Cover grill; cook 6 to 8 minutes, turning 2 or 3 times, or until beef is of desired doneness.