It's a giant sock. I don't know why this hadn't occured to me before... a Christmas Stocking is a giant sock.
To accompany the Santa Hat, I'm making a stocking. Using Van Dyck again, but much smaller needles. The fabric should be dense to hold up to the weight of the oranges and chocolates it will need to hold.
Pics to follow, but it's essentially a 50-stitch sock on 6mm dpn (a 40cm/16 inch circular works, too). The leg is 30cm/12 inches or so long. I did about 3cm/1 inch of k1p1 ribbing at the top because I'm planning to create a trim out of the same Santa Ana I used for the Hat. But if you want a plain sock, you'd need about 10cm/4 inches for visual balance.
I discovered is that a proportional foot looks odd, so keep the foot to about 20cm/8 inches or so before you decrease the toe, and do the decreases quickly -- every round seems to work.
I haven't got to the trim yet, but I'll probably do it the same way I do the trim on mitten cuffs. Pick up stitches partway down the leg, and work up a tube long enough to be folded over into the leg. Details once it's done.
Make a hook out of 15cm/6 inches of 4-stitch i-cord... fold in half and attach to top, just inside the cuff.