Green Chili Mac & Cheese: http://thelunacafe.com/world-famous-green-chile-mac-cheese/
Carmelized Sweet Potato, Garlic, and Rosemary Mac & Cheese: http://www.delish.com/recipefinder/sweet-potato-garlic-macaroni-cheese
Truffled Macaroni Gratin: http://www.seriouseats.com/recipes/2009/12/truffled-macaroni-and-cheese-gratin-recipe.html
Lightly Cheddared Spinach Ricotta Mac&Cheese: http://www.food52.com/recipes/10495_lightly_cheddared_spinach_ricotta_mac_and_cheese