By the time HP unveiled its first Ultrabook, the Folio 13, other heavyweights like Acer, ASUS, Lenovo and Toshiba had already gotten a head start of up to several months. But being fashionably late to market may have worked in Hewlett-Packard's favor: the Folio 13 ($900 and up) is temptingly priced for what it is. Even the base model comes stocked with a 128GB SSD, backlit keyboard, HDMI port and Ethernet jack -- specs that undercut the ASUS Zenbook UX31 and 13-inch MacBook Air, and render the $900