Only Laser/Radial and RSX are really ONE DESIGN . The others are BOX RULE classes, more than one brand produces the boats.
Star have Lilia, Mader etc etc etc.
470, Yingling, Tornado, Finn all have more than one boat builder too. The same with sails, you can use whatever sail brand you want to, except those classes.
I agree when Sergio says that Olympics do nothing for the sport and I don't think windsurfing needs to be at Olympics at all.