A report by DigiTimes says that Acer's gearing up to launch a 15-inch ultrabook, spurred on by positive sales of its 11- and 13-inch models. The news comes from sources at Taiwanese manufacturer Pegatron, who is reportedly set to produce the new models, rather than Wistron who currently builds Acer's ultrabook lines. The price is possibly the most startling thing, here: the sources suggest that the new ultrabook could launch for as little as $699, well below the $1000+ mark of the current crop of smaller models. While there's no indication of a launch date, a 15-inch ultrabook could give Acer a significant advantage over its competitors, especially in light of the rumor that surfaced late last month suggesting Apple plans to release a 15-inch MacBook Air in early 2012. Neither Acer or Pegatron were willing to comment on the matter when asked by DigiTimes.