I don't have a video link or anything but I think I would try a sewn bind off. It looks attractive and I think it stretches enough. You use a nice long tail and thread it through a tapestry needle and go purl wise through the first 2 stitches on the left hand needle and then back knit wise through the first stitch and then let that one off. Keep repeating those two steps. On the last one you go purl wise into the last stitch and the first loop at the beginning of the cast off and then back through the stitch again and take it off.
You can get different degrees of tightness with this. Just don't pull on things real hard as you go and it should stay loose and stretchy.