Apple may have a "major product launch" scheduled for May 19th or shortly thereafter, a source with the company suggests. The date marks the 10th anniversary of Apple's retail stores, but some unusual preparations are said to be on the way for the weekend. A special overnight shift is expected to run from Saturday night through to mid-Sunday, for instance, with about 10 to 15 people participating at each store. This includes a mix of all "visuals" workers, a manager, a business team member, some Geniuses, a backroom worker and some gener