I used very heavy-weight Pellon iron-on facing and some canvas material.
Here are the components:
|Heavy Weight Pellon|
It was a fun little project, but I don't think I would recommend it. It is REALLY hard to get the stitching even on the rounded corners (as in, I failed at this- see picture). Plus, the cover has to be precise or the iPad will be loose. I ended up buying a cover on sale somewhere that is a tighter fit, but I'd use this concept for covering other things.