Here's an interesting concept for a case meant to make the iPad usable for blind and visually impaired customers. The Omnifer almost covers the iPad completely, save for a small portion of the screen, and adds raised Braille buttons.
What's really cool is that the Omnifer is more than Braille buttons slapped onto a case. Instead, gas stored inside the case raises and lowers the Braille characters, making different ones available, depending on what's on the iPad's screen. The gas pockets are filled with a chemical that expands when exposed to light. The portion of the screen beneath the buttons will light up as needed to raise the proper characters. In this way, a user could "stream" text for reading via Braille.
It's very cool and, as we said, still in the concept stage. It's also a 2011 IDEA Award entry. Good luck to the entire Omnifer team.