Prepare the cornbread according to the package directions. When the cornbread has cooled, crumble it into pieces to yield about 2 cups of crumbled cornbread.
Preheat the oven to 350°F.
In a large skillet over medium heat, cook the bacon until crisp.
Add the onion, celery, and bell pepper and sauté for 2 minutes over low heat; set aside.
In a medium pan, melt 4 ounces of butter over low heat.
Add the milk, cream corn, whole kernel corn, jalapeños, pimentos, salt, and sugar and cook until heated through.
Add the sautéed bacon and vegetables and 1 cup of cornbread crumbs to the pan. Cook until heated through, stirring frequently.
Transfer the mixture to an 8x11-inch pan.
Moisten the remaining cornbread crumbs with the remaining butter and sprinkle them over the corn mixture.
Bake at 350°F until the crumbs are lightly browned.