Looking for removable decals

I have a Winnebago Minnie 2201DS. The back wall of the TT has no windows, therefore there is only a huge yellow empty space on the back with only the Winnebago label across the top of the wall on the outside.
Does anyone know where I may be able to find large removable decals to put on the wall and change from time to time? By large, I mean around 24" plus in size so it can be seen by more than a few feet away.
Thanks