Horse Trailer parts

Trailer parts
I am looking for matrerials for trailers "horsetrailers".
Windows "ca. 35x50 cm opening" for sides,
Hats for ventilation on top "50x40 cm" and axles, overruns and rims with tires 750 kg 1000 kg 1300 kg 1500 kg and 3500 kg

Regarns