1. Place roast in 3- to 4-quart slow cooker. Cover and cook on Low 8 to 10 hours (High: 4 to 5 hours). Remove roast from cooker; discard juices. Use tongs or 2 forks to pull pork.
2. Heat sandwich press. Rub garlic butter on interior of bread onto exterior of loaves.
3. Layer Cheddar and Provolone cheese on bottom halves of bread. Top with pulled pork, macaroni and cheese, and Swiss cheese.
4. Place top bread on sandwiches. Use hands to flatten sandwiches before placing in sandwich press. Cook until bread is browned and cheese is melted. Cut each loaf section in half to serve.