I suggest you leave a message in the RAM Owners portal of the RAM web site to this effect. List the names of all the dealers you have contacted. They may (as they did for me) twist the arm of a dealer to take your vehicle. But note, they have no "obligation" to do this; nor does the dealership network have an obligation to equip their shops to handle anything that someone (like Dynamax) wants to hang on the back of their C&C products. When Dynamax chose this product, I suspect they were given the assurance of a nationwide network of dealers only no one thought to check into the height, weight, length issues because most 5500s are serviced by fleet shops owned or contracted to the 5500 operators.
Ford is a bit different in this respect having sold RV/Ambulance combos for longer and to more smaller operators or individuals than Dodge over the years. And Ford "invented" this version of the Super C as RVs have been built on their F550 C&C at least since 2013. GM does not yet have an RV product on their C&C. So dealers generally have little incentive to build their service facilities to accommodate us.
If you fail to get a response from RAM/Dodge/Stellantis, then I suggest you do the rounds of the commercial truck service businesses in your area and see what they can do. Warranty will have to be handled by reimbursement and your documented attempts to find a dealership will be needed to support your claims.
Thank you. Looks like that is what I will have to do. I've called every dealer in the Las Vegas area. None of them will do it. Hard to believe in a larger city like this.