Well there already is broom appearances on the store which you can buy to change the appearance of whatever broom you have. This idea, however would break the EULA terms and conditions as it would be giving other players an advantage around the server. Maybe a broom appearance of flying animals perhaps? That would be quite hard to make the texture's for though, good idea but theres more practical stuff the server should be focusing on.
Im pretty sure the game design team is working on this if not something similar as they were or are looking for people to help out create it based on a post made on the home page. Let me paste it here for you to read: "Main Story Line - This area of GD focuses on writing and building Potterworld’s very own story-mode. This rank requires you to be staff." Expect this to take a whole though as I believe it is going to require a lot of hours of work for them to create this main storyline. :')
