I am sure this idea has already been discovered. However, I have not yet seen it :). I was thinking about a sandwich press the other day when I decided that my waffle maker would do the trick. My kids LOVED the sandwiches and have begged for them everyday since.
Make a sandwich (peanut butter without the jam, cheese, meat and cheese...), butter the outer bread slices as you would a grilled cheese sandwich, and...
press it in your ungreased preheated waffle maker until lightly browned. This is super fast and tastes delicious!