Hmmm....sheet styrene maybe? Might get a tad heavy, though.
Think I'm going to make this 1st gen sunshade non-folding. More bulk to lug around, no doubt, but sturdier maybe, if all the seams are hot-glued and more or less rigid. If I find the time, I may start actually contructing it this weekend.
I did find a very slim silicone 'case' that still fits in the controller's iPad holder, and gives at least some corner protection to my iPad. I'm thinking about integrating that into the sunshade somehow, maybe just by velcroing the sunshade to the back of the case. Seems like it might work. I get paranoid about dropping a 'nekkid' iPad, Murphy makes sure it will strike causing the most damage possible. You can guess how I know this...
I'm sure it seems I'm putting way too much thought into this little project, but I enjoy tinkering just for the sake of tinkering sometimes, know what I mean?