I like a good I-cord bind off, and have used the technique quite a bit, most lately in my Kenneth Street Slippers and in my upcoming Octopus Slippers. (They’ll be out March 17; I’ll update this post with a link when there’s something to link to. In the meantime, here’s a sneak preview, showing the grafted bind off.)

One of the things I like about this bind off is that you can graft it closed, making an almost invisible join. I’ve been meaning to draw a tutorial showing how to do this graft for a while; the new pattern seems like a perfect opportunity. So here’s how I do it:
Set up
After all project stitches are bound off and only the I-cord stitches remain, slip stitches back to the left needle. (If using DPNs or a short circular needle, simply slide the stitches to the other end.) Cut yarn, leaving a tail about 8 in/20 cm long. Thread tail onto a yarn needle and bring to the right-hand side of the stitches.
Step 1
Bring yarn through the first stitch purlwise.
Step 2
Bring yarn behind the legs of the corresponding stitch in the cable cast on at the beginning of the I-cord: if your first stitch in Step 1 is next to the wrong side of the fabric, the corresponding stitch at the beginning of the I-cord is also the one next to the wrong side.
Step 3
Bring yarn through the first stitch on the left needle, knitwise.
Step 4
Slide first stitch off the left needle and tighten the new graft stitch so that the new stitch matches the I-cord bind off stitches.
Repeat
Repeat steps 1-4 for remaining I-cord stitches. Weave in the end to secure it.