I am building some cabinets for my RV. They are long skinny overhead cabinets. I would like to buy or make a 48" long by 12" wide slab cabinet door that is paint grade. I am considering MDF or Baltic Birch plywood. Weight is an issue in an RV so I would prefer to use plywood. Will I have a problem with a door this long and skinny warping? Would it work if I attached some stiffeners to the back of the door?
My other option would be to buy some shaker style doors that have a frame if they will be less likely to warp.