Preheat oven to 350 degrees F. Place artichoke hearts in a fine-mesh sieve. To remove excess liquid, firmly press on artichoke hearts with paper towels. Chop artichoke hearts. Set aside.
Stack the 2 ounces prosciutto or the 2 bacon slices; snip or cut cut crosswise into thin strips. Separate pieces as much as possible. In a medium skillet cook and stir prosciutto or bacon over medium heat about 2 minutes or until brown and slightly crisp. Add arugula; cook and stir for 1 minute more. Set aside.
In a large bowl stir together sour cream and flour until combined. Stir in mayonnaise and roasted peppers. Stir in 1/2 cup of the cheese, the green onions, artichokes, and the arugula mixture. Transfer to an ungreased 9-inch pie plate. Sprinkle with the remaining 1/4 cup cheese (if desired, set aside 1 tablespoon of the cheese to sprinkle on just before serving).
Bake, uncovered, about 30 minutes or until edges are lightly browned and mixture is hot in center. Cool for 15 minutes before serving. If desired, sprinkle with additional prosciutto or bacon and any reserved cheese. Serve dip with crackers and/or baguette slices.