I've looked into making one. Here is a link to a functional and creative swift by Webecca: the Tilta Swift. I might make one some day, but why?
I have a yarn swift with much more to offer than that fancy Italian umbrella skeleton, or the homemade dollar store version (as wonderfully inventive as it is). Mine can adjust to the width of the hank automatically anywhere from 6" to 6' in diameter. Mine can tell me to slow down the winder while it carefully untangles a stubborn knot. Mine tells me jokes and that it loves me. Mine cooks my dinner and rubs my back. How much would you pay for one of those? I say "Priceless".