i've made about half a dozen bags for the kindle. no pattern, just seat of the pants sewing. i make a cardboard "box" open on one end and big enough to hold the kindle with a little wiggle room. then i cut regular fabric for a liner, sewing it shut on one side and the bottom and leave extra at the top. then i cut the fabric for the outer shell (prequilted fabric for the outer shell). i make it to fit pretty close. then i sew a zipper into one end making sure i use a big enough zipper to get the kindle in (and the "box"liner. i make a pocket to hold the cord and glasses or cell phone or ipod. i put a velcro closure on the pocket.
some of them i did a wrist strap type handle, some with purse style of handles.
then i check to see where i want to bottom seam. then sew the bottom seam. turn right side out again. push the box into the outer case, then put in the liner. i cut a piece of grossgrain ribbon twice the length of the kindle plus, tie a knot in one end and put the other end at the midway point on the zipper, hand sew the lining along the zipper (and the ribbon). the ribbon allows you to pull up on the knot and slide the ereader out easily.
i don't know if any of that made any sense, but it works for me.