Here are two more ideas for you Jessica and Hannah. Ratatouille can be made ahead and chilled. You butter the bread so the Ratatouille doesn't soak into the bread and make it soggy, nevermind that it would add richness and elegance to this appetizer.

Cold Ratatouille on Strips of Buttered Rye Bread
5 to 6 servings depending on how you use this (Many more servings if used on rye bread as an appetizer)

This recipe for Ratatouille comes from the book Helen Corbitt Cooks for Company. "This is the most versatile of all vegetable dishes. You may use it hot or cold, as an hors d'oeuvre, salad, or main dish; keep it covered in your refrigerator for several days. I like to put Ratatouille in crepes and use for luncheon or brunch."

3 medium-sized zucchini
1 medium-sized eggplant, peeled
4 tomatoes, peeled (You can use 1 or 2 small cans of Italian peeled plum tomatoes, drained)
2 green peppers (use one red one if you like)
1 cup thin-sliced onion
1/4 cup salad oil, half extra virgin olive oil or all olive oil
1 clove garlic, finely minced (I think I would use 2 cloves)
Salt and Pepper to taste
Optional and not in Helen Corbitt's recipe are:
2 Tbsp. chopped fresh flat leaf parsley,
1 tsp. dried basil,
1 tsp. dried oregano
Also, not in Helen corbitt's recipe but in Craig Claiborne's recipe from The New York Times Cookbook:
3 Tbsp. flour

Heat the oil in a large skillet, add the garlic and onion and saute until the onion is transparent.

Meanwwhile, slice the squash and peel and cube the eggplant. Flour the pieces lightly.

Add the squash, eggplant and green peppers to the skillet, along with the herbs, if you are using them. Cover and cook slowly (low heat) for about 1 hour. Add the tomatoes and simmer, uncovered, until the mixture is thick. Season with salt and pepper. Serve hot or cold.

Another idea for an elegant appetizer would be fresh figs or melon slices wrapped in Prosciutto. You could use both cantalope and Honeydew melons. Wrap then with Prosciuuto. These would make a colorful presentation with the red color of the Proscuitto. Present on a tray lined with red or green leaf lettuce leaves.