2005 TRD O/R rear bumper rust

I live in New Hampshire and bought a new 2005 Quad Cab Tacoma in September 2005. My truck has only seen two very mild winters worth of salted road conditions. I wash the under body of my truck frequently. This spring I noticed that surface rust is breaking out all over my truck’s frame, at the weld joints, on the flat surfaces of the frame and anywhere something is bolted to the frame. I have talked to the service department at Toyota of Nashua, NH where I bought the truck and they state that no other customers have brought this problem to their attention as yet. I am a mechanical engineer and I design and work with metals, undercoating and painted finishes all the time. Based on my experience, it is my opinion that a properly paint two-year-old truck frame should not have this much rust breaking through the paint on the frame as mine does. All Toyota advertisements I have always seen, stress the durability and extremely long service life expectancy of their vehicles. The entire reason I bought my Toyota was based on their long-standing track record of high quality and customer satisfaction. Working with the dealership we escalated this situation to the New England District Service & Parts Manager trying to get Toyota to repair the rust break through problem. I presented the idea that there may be a Toyota design problem with the undercoat and paint system specified for the 2005 Tacomas and or that the coating materials were not applied correctly to my specific truck. The New England District Service & Parts Manager is basically stating that all frames start to rust eventually and that Toyota has no obligation to repair the frame rust even thought the truck is only two years old. My local dealership is now saying this problem is in the hands of New England District Service & Parts Manager and if I am not satisfied with their response I may have to go through the arbitration process with corporate Toyota USA to get this rust problem addressed and corrected.