Meanwhile, melt butter in a large skillet over medium heat. Gradually whisk in flour until smooth; cook, whisking constantly, 1 minute. Gradually whisk in 2 cups milk and next 3 ingredients; cook, whisking constantly, 3 to 5 minutes or until thickened. Stir in Cheddar cheese and pimiento until melted and smooth. Remove from heat, and stir in pasta.
Line a 13- x 9-inch pan with plastic wrap, allowing several inches to extend over edges of pan. Pour mixture into prepared pan. Cool slightly; cover and chill 8 hours. Remove macaroni mixture from pan, and cut into 1-inch squares.
Stir together breadcrumbs and Parmesan cheese in a shallow dish or pie plate. Whisk together eggs and 1/2 cup milk in another shallow dish or pie plate; dip macaroni bites in egg mixture, and dredge in breadcrumb mixture.
Pour oil to depth of 1 inch in a large skillet; heat to 350°. Fry bites, in batches, 2 minutes on each side or until golden.