Cut each jalapeno in half lengthwise and remove the ribs and seeds. A baby spoon or demitasse spoon works well for this. (You may want to wear latex gloves)
In a mixing bowl, combine the cream cheese, Mexican cheese, chili powder and garlic salt until well blended. Stir in the scallions. Transfer the mixture to a quart resealable plastic bag.** With a scissors, cut about 1/2-inch off one of the lower corners to make a pastry bag. Squeeze the cheese mixture into the jalapeno pepper halves.
Cut the bacon crosswise into pieces long enough to wrap around the middle of each jalapeno, seam-side down.
Arrange on a baking sheet covered with foil or parchment paper.
Roast the jalapenosat 350° for 30-40 minutes or until the peppers have softened, the bacon is cooked, and the cheese is hot and bubbly. Let cool for a few minutes before serving.
**I did not use the resealable bag. Instead, I just used a small knife and spread the filling into the peppers.