I've been using a Windows RT Surface from Microsoft, and while it's no iPad, it does have a built-in stand. But that stand only works in landscape mode and has a limited range of motion.
Rain Design has an answer: The iSlider ($49.00) is a compact folding aluminum, plastic, and silicone offering that looks right at home with Apple products.
In fact, the stand looks a bit like a cross between Apple's Magic Trackpad ($69.00) and the original iPhone, thanks to the black plastic strip at the edge of the otherwise all aluminum body.When you pull on that plastic strip, the iSlider slides open to reveal an adjustable support stand with over a dozen angles. It accommodates a variety of tablets, with or without a case.
The iSlider is a bit bigger and heavier than other portable stands, but it is quite versatile and well made and has earned a spot in your gadget bag, or even your pocket!