Does anyone have a link to the Knitty article (or any article, really) about that method of kind of double knitting to make something nice and thick and warm? It isn't just doubling up the yarn, but a different way of actually stitching, I think.
Nevermind! Found it. Here it is, in case any one else is interested.
I just finished scanning a book I found at the library today: TwinedKnitting by Brigitta Dandanell-Ulla Danielsson. If you are interested in this it has some beautiful patterns, as well as old pictures and history of this type of knitting.
there are a couple of other places for more about double knitting http://www.knittinghelp.com/knitting/advanced_techniques/ and there is diy network this is a tube top design