To show off the ham and cheese filling, slice roulades after grilling. The steak spirals, with the tomato relish and grilled zucchini, make an attractive entrée.
Place each piece of meat between 2 sheets of plastic wrap, pound to 1/8-inch thickness. Place in plastic food-storage bag.
In small bowl, whisk together the 1/2 cup oil, the vinegar, Worcestershire sauce, garlic, salt and pepper. Pour 1/2 cup marinade into small measuring cup; add the 2 tablespoons oil; add this mixture to meat in plastic bag; seal.
Cut each zucchini lengthwise into quarters, then crosswise in half. Place in clean plastic food-storage bag with 1/4 cup of remaining marinade; seal.
In large bowl, toss together tomatoes, remaining marinade and basil; cover. Marinate meat, zucchini and tomatoes in refrigerator 3 hours or overnight.
In medium-size skillet, heat oil over medium-high heat. Add scallions; sauté 3 minutes. Remove from heat; add bread crumbs, Parmesan and basil.
Prepare outdoor grill with hot coals arranged for direct grilling, or heat gas grill for direct grilling.
Remove meat from marinade; discard marinade. On 1 piece of meat, place 1 slice ham and 1 slice cheese; spread 2 slightly rounded tablespoons of bread crumb mixture over top. From short end, roll up meat, jelly-roll style. Secure roulade with wooden picks. Repeat with remaining meat, ham, cheese and bread crumb mixture. Drain zucchini from marinade.
Grill roulades about 10 minutes, covered, turning every 3 to 4 minutes, or until cooked through. Grill zucchini 6 minutes, turning once, or until tender. Serve with the tomato sauce.