I bought 6 cypress supers last year from a website. They were very helpful and sent the order promptly. The wood was very nice, and I am sure will last a lifetime because of the oils in it. However, knowing what I know now, I will just make my own out of pine 1 X 8 from a big box store and paint the outside with copper napthalene and then a coat or two of whatever, spar varnish or white latex. Even if you don't have your own table saw and tools, buying precut pine supers is way cheaper. It will last a long time if you take care of it.
Dave