Portable Metal Sauna Jacuzzi Trailer

I want to turn a standard road-legal trailer into a combined sauna and Jacuzzi that I can tow to lakesides and festivals. The shell, frame and all structural elements must be metal so the unit stays rigid during transport yet still looks sleek once parked... (Budget: £20 - £250 GBP, Jobs: 3D Design, 3D Modelling, AutoCAD, CAD/CAM, Electrical Engineering, Mechanical Engineering, Plumbing, Solidworks)