In a mixing bowl, stir together the pork shoulder and pancetta with your hands until well-mixed. Add pepper, salt, wine, oregano and chili flakes and mix until well-blended, again with your hands. Work quickly here so that body temperature does not change the texture of the fat.
Set up the sausage stuffer and place the casing over the funnel feeder. If you do not have a sausage stuffer, form the sausage into 1/4-pound logs by hand. If using a sausage stuffer, stuff the sausage into the casings, twisting every 3 1/2 to 4 inches, to yield 4-ounce sausages, and form 22 to 25 sausages. Prick them all over with a needle and set aside in a cool place.
Bring 6 quarts of water to a boil and add 2 tablespoons salt. Set up an ice bath next to the stove top. Blanch the broccoli rabe for 2 minutes, refresh in the ice bath and drain.
Preheat the broiler. Place the pricked sausages in an oven-proof pan and broil until halfway cooked, 5 minutes per side. Place the pan over medium heat and continue to cook until the sausages are deep golden brown, 6 to 8 minutes. Add the garlic and broccoli rabe and, stirring, cook until the broccoli rabe is hot, 5 to 7 more minutes. Meanwhile, on a small sheet tray, toast the bread crumbs under the broiler until golden brown. Remove to a small bowl, add the oil and mix well. Pile the broccoli rabe on a plate, sprinkle with the bread crumbs, place the sausages next to the broccoli rabe and serve.