Cut the bacon slices in half lengthwise, and then slice into rectangles about ⅛-inch wide.
Place in a cold skillet over low heat, and cook until crisp. Drain on paper towels and set aside.
In a large mixing bowl, whisk the egg whites, sugar, and maple syrup together slightly, to combine.
Place the bowl over a medium pot of simmering water, on medium-low heat and cook for about 10 minutes, stirring frequently, until the sugars have completely dissolved and the mixture no longer feels gritty when rubbed between the thumb and forefinger.
Remove from heat and whip on high speed until the meringue holds stiff peaks and the mixture has completely cooled. (There should be no hint of warmth left.)
Add in the butter, a tablespoon at a time, whipping on high speed. (If the mixture begins to look curdled, keep whipping until it comes back together before adding more butter. If it is too runny to pipe or spread properly, place the mixture (in the mixing bowl) into the refrigerator for 15-20 minutes, and whip again, until fluffy and thick.)
Pipe the maple buttercream on the cupcakes, and garnish with crisp bacon sprinkles.