Special equipment: a smoker (the stand-alone or grill-top variety) and 2 cups pecan wood chips soaked in water for 20 minutes
For the pork tenderloin: Combine the paprika, salt, garlic powder, black pepper and cayenne in a small bowl. Store in a tightly sealed container for up to 6 months.
Clean the pork tenderloin of any silverskin or tough membranes with a sharp paring knife. Rub the tenderloin well with 2 tablespoons of the seasoning mix. Let sit for 1 hour at room temperature or up to overnight in the fridge.
Set up a smoker according to the manufacturer's instructions with 2 cups soaked pecan chips (either directly on the coals or in a smoke box) and preheat to a medium-low, about 265 degrees F. Add the pork and cook until the internal temperature reaches 140 degrees F, about 1 hour. Let rest for 10 to 15 minutes and then slice into thin slices.
For the coleslaw: Mix the cabbage and carrot in a medium bowl. In a small bowl, combine the mayo, chives, red wine vinegar, celery seeds, salt and black pepper. Toss with the grated vegetables. Set aside.
For the fondue sauce: Melt the butter over medium heat in a heavy-bottomed medium pot. When it has stopped bubbling, add the flour. Stir with a wooden spoon until it looks like a paste. Cook, stirring quickly, for about 1 minute. Pour in the milk and light beer and bring to a boil, whisking constantly. When at a boil, lower to medium-low heat and allow to thicken. This should happen quickly, about 3 1/2 minutes total. Gradually add the Swiss cheese while stirring, and allow the mixture to emulsify. Season with the cayenne, nutmeg and salt. Remove from heat immediately. The sauce should be cheesy and thick, yet pourable with a spoon. Keep warm.
For the sandwich: Preheat a cast-iron griddle over medium heat.
To assemble: Lightly brush the inside of a roll on the top and bottom with some softened butter. Cook cut-side down on the griddle over medium heat until toasted, about 3 minutes. Spread 2 teaspoons mustard on the bottom piece. Add 2 ounces sliced smoked pork, 1 slice bacon, 1 slice ham, 2 dill pickle slices and 1/2 cup coleslaw. Add the top bun.
Brush the top and bottom of the bun lightly with some softened butter and add the sandwich to the griddle, pressing to flatten with a spatula or another cast-iron pan, and cook until crisp and brown, 4 to 6 minutes. Remove from the heat to a cutting board. Repeat to form 4 sandwiches total.
Ladle 1/4 cup of the fondue sauce into 4 tiny ramekins. Serve hot on the side with the sandwiches for dipping. Reserve the remaining pork tenderloin for another use.