I've got a need for a long ally box. About 95" x 40" x 16", a long, low box probably with 22.5" long gullwing lift up lids at each end and a ~40" central section. I was thinking about using 3/32" 5052. It's gotta fit sails, for a boat trailer, and assorted gear and be lockable to leave it overnight reasonably securely. All the premade boxes that people are selling around here are nowhere near this long, which makes me think that there might be structural issues I'm not aware of. Is this a feasible design? Is there a reason no-one makes premade boxes this long? Would I need to think about some internal bracing using square tube or something?