Flags are usually only a few colors and if they have a symbol it tends to be pretty simple. I'm thinking the Mustache flag would be basically the Canadian flag, just remove the maple leaf and put a hybrid bike with cargo rack right in the middle.
Now money, that's an area you can throw a lot of symbols on. I think mustachian currency would need to have pictures of bikes, home improvement tools, fresh fruits and veggies, libraries and books.
