Put the bacon on a large rimmed baking sheet, place in the oven and heat to 400. Cook the bacon through — until it is chewy and going to crisp — approximately 15 minutes. Remove the bacon from the pan, and set aside. There should be a couple of tablespoons of bacon fat in the pan. If there is more, discard it. Add the butter to the bacon fat, then put the potatoes, onions and red peppers onto the pan, and stir to coat. Spread the potatoes, onions and red peppers out evenly across the pan, and return it to the oven for 20 minutes or so, then take it out again, and use a spatula to turn everything over. Cook for another 20 minutes or so, or until the potatoes are beginning to crisp, then turn them once more and cook for an additional 10 to 15 minutes. Meanwhile, in a small bowl, whisk together the sour cream, lime juice and minced chipotles en adobo, to taste. Season with salt and pepper. When the potatoes are well crisped, take the pan out of the oven, and season with salt and pepper. Dice the reserved bacon, and scatter it on top of the potatoes, then top with the shredded cheese. Stir to combine, and return the pan to the oven until the cheese has melted, approximately 3 to 5 minutes. Tip into a mound on a warmed serving tray, drizzle with chipotle sour cream, garnish with the scallions and serve.