Preheat oven to 375 degrees F.
Sauté over medium/low heat the onion, garlic, tomatoes, summer squash, zucchini, eggplant, and basil in olive oil for 15 minutes.
Mix together the cooked rice with black beans and chili powder.
Combine this mixture with the sautéed vegetables.
Cut the tops off of the peppers and remove the ribs and seeds.
Spoon about 2 tablespoons of the rice/bean/vegetable mixture into the bottoms of the peppers.
Sprinkle on cheese and then layer 2- 3 more times, ending with cheese on top.
Bake in preheated oven until peppers soften, about 45 minutes.
Optional - Slice peppers in half, top with tomato sauce or slice the peppers and surround them with any remaining vegetable mixture and cook for 5-10 more minutes.