In a large bowl, whisk the vinegar, oil and sugar. Toss with the vegetables and celery seed; season with salt and pepper. Let the relish stand 30 minutes. Drain.
In a cast-iron or other deep skillet, heat the oil over medium-high. Melt the butter into the oil. When the butter foams, add the meat. Season with salt and pepper and cook, breaking up with a spoon, until browned, about 10 minutes. Add the onion, garlic, chiles and allspice. Cook, stirring often, until the onion softens, 5 minutes. Stir in the tomato sauce, stock, hot sauce, brown sugar and Worcestershire. Reduce the heat to low; simmer until thickened, about 2 minutes.
Serve the meat on the rolls and top with the blue cheese and relish.