ok here's a little tut for anyone interested:
i kept a ruler at the bottom for scale (the units are centimeters)
i could only find three needles of the same size so i knit it in the round on two needles. cast on to the two needles like you would otherwise (except more carefully because the thread is sort of slippery). the whole time you're knitting try to hold the elastic taught-- this way it will look even.
knit (very tightly and very carefully) and try not to drop any stitches. always insert the point to knit-- since the needles are being used as DPNs you'll be picking up the stitches from the dull size/the side with the hole. if your hands hurt, take a break and shake them out.
knit about 10 rows
cast off. i used a crochet hook that was the smallest size i could find (a B). i tried to illustrate the cast off but the photos came out a little blurry... its just a basic cast-off but the hook keeps the stitches from falling off the needle
cut the elastic with about six inches extra. below is the ring at this point
thread the needle with this extra elastic and whipstitch the ends-- since the ring is in stockinette it will roll inwards, so this gives it a more even look
the other reason for sewing it together is... tadaa, now you have a little pocket where you can just thread the excess and cut it and you dont have to sew in any teeny tiny ends.
enjoy! hope this was clear