I was in Best Buy yesterday and came across the Targus Lap Lounge which is for tablets with 10 inch screens. I've been looking for a stand to use on my lap, as the new iPad can get heavy after a while. It also works with my android tablet. It has an adjustable angle. And the spring loaded clamp is solid, yet easy to open and close. It is basically a bean bag with a clamp attached.

I am surprised I haven't heard of it before...