1) Preheat the oven to 190°C.
2) In a heavy skillet, add the oil and heat over medium-high heat. Add the onion, carrot, celery, and garlic. Cook, stirring often until vegetables are soft, about 8 minutes. Set aside until cool enough to handle.
3) In a large bowl combine the sauteed vegetables, ground beef, chorizo, and diced poblano chilli.
4) In a medium bowl, combine the salt, pepper, cayenne, cumin, and eggs. Add the ketchup and sour cream. Mix well with a fork and pour it on top of the mixed meats. Sprinkle with bread crumbs and mix thoroughly with clean hands.
5) Put the mixture into a 20 x 30 cm loaf-pan. Bake until an instant-read thermometer inserted into the center of the meatloaf registers 70°C, about 40 to 45 minutes. Remove from the oven and carefully pour off any accumulated pan juices.
6) Meanwhile, heat a heavy frying-pan over high heat. Add the whole tomatoes, onion, garlic cloves, and serrano chillies. Cook, turning frequently, until lightly charred on all sides. Peel the garlic cloves. Add all the charred ingredients to a blender. Pulse until chunky, then pour into a small skillet. Stir in the sugar, chipotle chilli and mustard. Bring the mixture to a boil over medium heat. Cook until slightly thickened, about 4 to 5 minutes. Season with salt, to taste.
7) Slice the meatloaf and arrange on a platter. Spoon the salsa-glaze over the meatloaf and serve.