Hard-cook eggs: gently place eggs in a large saucepan or pot. Add cold water, enough to cover eggs 1 ½ inches. Heat on high heat until water is boiling. Remove from stove and cover pot with lid and let stand for 12-15 minutes. Remove eggs from pot and allow eggs to cool before peeling.
When cooled, peel and set aside.
Fry the pancetta in a large skillet over medium-high heat, until all pieces of pancetta are dark in color, crispy on the edges, and most of the fat on the pancetta has been cooked away. Remove the pancetta from the skillet onto a plate covered with several paper towels; set aside.
Halve the hard-cooked eggs lengthwise, and place the yolks into the bowl of a food processor.
Add all of the remaining ingredients (mayonnaise, vinegar, pepper, sugar, celery seed, chives) to the food processor, except for the pancetta. Puree until smooth.
Reserve two teaspoons of the pancetta for garnishing the finished eggs, and add the remaining pancetta to the food processor. Pulse until well combined.
Spoon the egg mixture into a large plastic storage bag, snip the end off, and fill egg whites.
Garnish the filled eggs with the reserved pancetta.