Hot on the heels of its iPad Air keyboard case Ultrathin Keyboard Folio, Logitech has released the Ultrathin Keyboard Cover for iPad Air ($100), a reduced footprint version of the iPad 2/iPad (3rd/4th-Gen) model we reviewed last year. Once again, the concept is to match a physical Bluetooth keyboard to the materials, shape and size of the latest full-sized iPad, protecting the screen while leaving the rest of the body exposed. Logitech has…