REUTERS: Publishers are placing big bets that Apple Inc’s iPad will kick-start a commercially viable transition to digital magazines and newspapers — even though few executives have laid hands on the tablet ahead of launch. In fact, many publishers likely will not announce their iPad applications until after the tablet hits U.S. stores on Saturday, due to the many constraints that Apple has placed on allowing its partners access to the device. While media content is critical to the success of the iPad — a 9.7-inch tablet that looks like a large iPhone and aims to bridge the gap between a smartphone and a laptop — Apple has been typically secretive about its plans. Media executives say they have had to test out the iPad in situ at Apple’s Cupertino, California office, or agree to extremely restrictive security measures to get one off-site. “We were offered the opportunity to have an iPad in the building but the security implications were so high, it wasn’t worth it,” said one publisher who did not want to be identified ahead of the iPad launch. Only a lucky few received a personal visit from Apple Chief Executive Steve Jobs, who was in New York earlier this year to show off the iPad to a few publishers including the Wall Street Journal and the New York Times. Despite the restrictions, the iPad’s full color touchscreen is seen as a game changer for media companies that have long struggled to make money off digital content, which most consumers expect to get for free or at a very low cost. Book publishers see a new chance to get their electronic offering right — and win more bargaining power if the iPad emerges as a viable rival to Amazon.com Inc’s Kindle. “We have all struggled in this industry to find an online model that works successfully in terms of content and the consumer’s propensity to pay,” Penguin Books Chief Executive John Makinson told a recent media conference in London. MORE