I want to try it too, Jan, but I have a feeling it will produce an "imperfect graft" because of the casting on, sort of like a provisional cast on that comes up a stitch short and so things don't align precisely. That said, it could still be something I would want to use because it would be less obvious than just changing colors. I think my crochet hooks that attach to my cables would make getting the yarn through the stitches quick and easy if I were doing a lot of them and circs would eliminate transferring stitches from needle to needle as he does.
Cheating is an option. . . . Cheaters never win and winners never cheat, but smart knitters who want to retain an iota of sanity do, cheerfully. ~~Kory Stamper