A company like Sign-A-Rama applies graphics to fleets of modern rescue vehicles. IMHO (and carrying a degree in Graphic Design) they applied what they know to your MM which does not fit vintage. Yeah, they tried on window graphics but still a fail.
There's nothing wrong with using traditional MM window graphics. Don't recall ever seeing optional long version in person that Steve Loftin mentioned, so maybe that would be your uniqueness answer.
If you really wanted unique however you wouldn't have chosen oh-so-popular Omaha Orange. Gold (leaf included) is inherently gaudy. Another piece of your 'unique' puzzle can include silver leaf (actual, not vinyl) on a door logo, which would really pop burnished on an orange base. Find an exact style of logo desired, figure out what you want your rig to say, and give those two criteria to designer. Take guesswork out and don't waste designer's time trying to figure out what you want.
Leave other graphics (rear) off entirely. Too busy. Less is more. (<---That's classic.) You don't want your rig looking like it was just accessorized at Pep Boys, do you?