The next-generation iPhone, expected to be released around September of this year , will be “thinner and lighter” than the iPhone 4. And while manufacturer Foxconn has had difficulty assembling the devices, Apple may try to move as many as 40 million by the end of the year. Component supplier sources that spoke to the Wall Street Journal corroborated recent rumors pointing to an 8 megapixel rear-facing camera and baseband processors supplied by Qualcomm. However, these same sources suggested that the new iPhone will be “thinner and lighter” than the current model. WSJ ‘s report adds to the conflicting rumors we have heard in the last few weeks regarding the next-gen iPhone’s form factor. Numerous sources, including those for Bloomberg, have said that the new device will look largely the same as the current iPhone 4. Sources for BGR, though, claimed that the device will have a “radical new case design.” Perhaps instead we will be ultimately treated to something between both extremes—a thinner and lighter version of the current form factor is certainly plausible. Nonetheless, we’re not convinced that the new iPhone will feature a significantly different form factor. WSJ noted that Hon Hai (aka Foxconn) chairman Terry Gou complained last month that iPhones and iPads are already difficult to assemble because they are so thin. “We hope to raise the yield rate and volume in the second half which will help improve our gross margin,” Gou said. That doesn’t seem possible if Apple plans to use a new form factor that is “complicated and difficult to assemble,” according to WSJ ‘s sources. More interesting is the fact that one supplier claimed to have been told by Apple to be prepared to ship enough components to Apple manufacturing partner Foxconn to build 25 million iPhones by the end of the year. Apple’s additional manufacturing partner, Pegatron, reportedly received an order for as many as 15 million next-gen iPhones . If both sources are correct, Apple could be forecasting iPhone sales of 40 million. That number may seem high, especially given the fact that the new hardware is not expected to be available until the latter part of the third quarter. But Apple already moved nearly 19 million iPhones in the first calendar quarter of this year, and that figure is double the amount sold the same quarter the year before. With Apple expected to announce another record quarter later this month, 40 million total iPhones in four months might not seem quite so far-fetched. Read the comments on this post