Before you take the time to build it, especially if you are not handy with tools, check out the one that John Flynn has.
I believe that is his name. He uses PVC pipes. I saw him in action at a show and I sat down to use it and found it very comfortable and easy to use. I believe he sells the whole setup, parts, or the instructions how to make your own. I think he has a web site. (I hope I have his name spelled right)