I have built a number of doe boxes for my lease from 1000lt IBC containers. This is my latest one, I use one for the body and ½ of a second one for the roof, the steel frame they sit in make a ideal tower, you can bolt two or three together to give you extra height. The one in the photo just requires a coat of green paint to finish it of. From 3 IBCs you will get two boxes and a couple of towers depending on how high you want to go.
Being made of plastic they are very light and water proof, of course they require no maintenance.