If you want to get your hands on RIM's BlackBerry PlayBook, you might be running out of time. It seems that the QNX-based device is no longer available in the US from retailers like Wal-Mart, Best Buy, RadioShack and Staples, with Amazon and RIM's own online store being the exceptions. We're wondering if this means newer PlayBooks are in the works -- we've already seen updated 4G LTE models out in the open and recent OS updates indicate the company hasn't given up on the much-maligned PlayBook. Potential upgrades include the upcoming BlackBerry 10 OS, and hardware improvements wouldn't be a bad idea (Perhaps a flip-out keyboard addition a la Microsoft Surface?). In any case, RIM might want to move fast if it wants any chance of competing in the increasingly crowded tablet space.