Apple might not have an iPhone 4 with a sliding QWERTY keyboard, but that doesn’t mean that accessory makers out there aren’t interested in capitalizing on that market. The Nuu Mini Key case for the iPhone 4 offers just that – a sliding QWERTY keyboard add-on for the iPhone 4. It’ll be going up for sale before the end of the year, and you can expect to pay around $60 for it. Too bad it doesn’t include a built-in battery for additional juice, eh?