Start by making a turkey broth. In a large stockpot, combine the turkey wings, onions, carrots, garlic, rutabaga, celery, bay leaves, and 1 gallon cold water (or enough to cover by at least 3 inches). Bring the water to a boil, reduce the heat and simmer for 45 minutes, skimming when you feel like it to remove any impurities that float to the top. Remove from the heat and strain into a large pot or bowl, pressing on the vegetables and meat to extract as much flavor as possible. Discard the vegetables, turkey, and herbs. Cool the broth to room temperature before storing in the refrigerator, or chill it down over ice first. When chilled, skim the surface again for any additional impurities. This can be done up to 3 days in advance.
Preheat the oven to 375 degrees F.
Toss the pumpkin in a large mixing bowl with the 1/4 cup olive oil, nutmeg, minced sage, salt, and lots of pepper. Dump the pumpkin onto a cookie sheet, spread it out to a single layer, and roast for 45 minutes or until very tender.
Now that you've got the elements, you can put the soup together. Put a large stockpot over medium-low heat. Heat the 2 tablespoons of extra-virgin olive oil, add the whole sage leaves, and saute for 1 minute. Add the pancetta and cook for 2 to 3 minutes to render out some of that delicious fat. Toss in the minced garlic and onion and cook for 2 minutes or until the onion is translucent. Add the cabbage and cook, stirring, for 3 to 5 minutes or until the cabbage is wilted. Pour the strained, cooled broth into the pot and bring to a gentle simmer. Taste the soup and then season with salt and pepper. Ladle the soup into bowls and garnish with several pieces of pumpkin and a drizzle of olive oil.