I would caution you that using any form of writing as a punishment might not be viewed in a good light by your administration.... for the same reasons that you don't want music to be a punishment.

Most kids don't want their parents to know they are not meeting behavior expectations at school. Calling a parent (before the kid does) is key because "the first word home is the word that is believed." I have stopped class, called a parent right there and asked for their "help" with their child that isn't meeting the behavior expectation. Unfortunately, they are interfering with the other students education, and this cannot continue. That kid usually corrects itself, and the others seeing you stop the whole thing will meet the behavior expectation because they don't want that same thing to happen to them.

Whatever you decide, good luck!