My two year old asked to be a drum major this halloween, I thought that was pretty original (he is obsessed with parades and marching bands).
I made everything for this costum, complete with detachable cape, tall busby, and trick or treat bag with drum design. I'm really pleased with how it turned out. He loved it! The basic pants and top were made using a pattern for a kids chefs costume but everything else I made the pattern up for. I used a cut down oatmeal container inside the hat to help keep it from caving in. All the blue fabric in the costume was left over from the bridesmaids dresses that my mom made for my wedding several years ago so it was a pretty cheap costume to make. The most I spent was on the blue fur for the hat which I had to special order because I couldn't find blue fur anywhere.
He had a great time marching around in it and blowing his whistle.