Have to admit, my can holder was made from scraps lying around the back garden. As long as you can line the three parts up well and have a decent base that allows it to keep stable, you're laughing.
Mine has a reasonable size base, a neck and a bar to hang all my four cans from. I even drilled a couple of holes in the base to stick things in, like adapters and plugs.
Start with something simple, after a short while you'll probably be making some epic stands. It's all down to what you can think of. :)