RIM just can't quit keyboards, and neither can many of its fans: even the BlackBerry PlayBook has an official Mini Keyboard case. It almost shouldn't be a surprise, then, that the company is applying for a patent on a tablet design with a stealthy keyboard built-in. The layout hides a full, hinge-attached QWERTY keyboard from critics (and accidental key presses) underneath a back-mounted cover. When an owner's urge to use physical buttons becomes overwhelming, the keyboard swings into action and relies on the cover as a kickstand. It's a clever solution to lugging around a separate keyboard or specialized case, but it's hard to say if RIM will implement what it's learning into a finished product -- the firm isn't in the best position to experiment with new tablet concepts, and we've already seen a few imminent solutions to the concealed keyboard problem from other vendors. That said, the patent does show that the folks in Waterloo would like to keep a love of keyboards alive in the tablet era, even if it requires some subterfuge.