This almost goes without saying, but it's truly been a wild ride for the iPhone 4 over the last three weeks. While most of us will just happily open our hands to Stevie J's freebies, there's one question that's still bugging us: what's actually holding back the white iPhone 4? Sure, Apple's now promised us an "end of July" delivery for its latest iTemptation, but it has yet to specify what the manufacturing difficulty is. According to Chinese newspaper 21st Century Business Herald, the problem stems from a little-known Chinese factory by the name of Lens Technology, which is apparently responsible for transforming fine raw glass into the majority of iPhone glass panels out there (and contrary to previous reports, there's no mention of Corning here). Read on to find out what's causing our invisible hero to stall.Lens Technology -- a rather bland name for a touchscreen glass manufacturer -- isn't exactly a household name to the average gadget consumer, but its list of clients tells a different story: Huawei, Lenovo, Motorola, Nokia, Samsung and more. Since its launch in July 1993, the company's set up several plants, including its latest site (circa December 2006) in Liuyang, Hunan that currently houses about 14,000 workers, which looks about right in the drawing above. While this is merely a fraction of Foxconn's 400,000 employees in Shenzhen, Lens' recent intake of some 7,000