Coincidentally, I met with a sign maker today for a work-related matter, and brought up the subject of RV graphics. They said they can make, or match, almost any graphic, and have a vinyl sign machine that can make decals four feet wide and forty feet long. The shop owner said that bigger machines can handle wider decals than the four feet he can handle. He's making custom door signs for our RV, and his prices are very reasonable. I'd be talking to the local sign shop!
Good luck with your project, and happy camping!
Elizabeth RVM55 and Mary
2014 Thor Ace 30.1
2014 Chevy Equinox V6 LTZ AWD