Nokia is again developing a proprietary smartphone operating system after announcing this past February that it would abandon both Symbian and MeeGo in favor of Microsoft’s Windows Phone platform. Citing multiple anonymous sources, The Wall Street Journal on Wednesday reported that Nokia’s executive vice president of mobile phones, Mary McDowell, is heading up the project. Code-named “Meltemi,” the new mobile platform is reportedly Linux-based and it is intended for use on low-end smartphones. BGR has independently confirmed the report, and we have learned additional details that paint an exciting new picture of the mobile industry should Nokia’s new OS realize its potential.

Updated with statement from Nokia.

The big question mark that the Journal’s report doesn’t address is what Meltemi — the Greek name for winds across the Aegean Sea from the north in the summer — means for Nokia’s plans with Windows Phone. Nokia’s chief executive Stephen Elop confirmed on multiple occasions that the company plans to offer Microsoft’s new mobile OS on high-end and low-end devices, thus continuing its efforts across all markets.

While the development of a new proprietary operating system has obvious implications for Windows Phone in emerging markets, BGR has learned that Nokia’s plans likely haven’t changed much since the Meltemi project began. Nokia still intends to offer a range of smartphones powered by Microsoft’s Windows Phone operating system, and this range includes entry-level, mid-range and high-end smartphones.

Meltemi, a source has informed BGR, is being built to eventually replace Nokia’s Series 40 platform, which currently powers the company’s feature phones. Nokia’s vision is seemingly to build an operating system with capability that reaches well beyond “S40,” but that can function on similar low-cost hardware. This new platform will be fairly capable, but our understanding is that it will not be a full-fledged OS intended to compete with the likes of Android, iOS and Windows Phone.

Nokia will build low-cost Windows Phones to address certain demographics, but Meltemi will allow the cell phone vendor to bring smartphone functionality to emerging markets at rock-bottom prices. The licensing fees, hardware requirements and other costs tied to Windows Phone, we’re told, would never allow Nokia to hit the price points it will achieve with Meltemi — not even with Microsoft’s upcoming stripped down version of Windows Phone dubbed “Tango.”

Nokia is the world’s top cell phone vendor by volume, having sold 461 million mobile phones in 2010 according to recent data from market research firm Gartner. A world where nearly all of those devices are smartphones would see countless new doors open for Nokia and for its hundreds of millions of customers.

UPDATE: Nokia spokesperson Kendra Petrone provided the following statement to BGR via email:

While we don’t comment on future products or technologies, I can say that our Mobile Phones team has a number of exciting projects in the works that will help connect the next billion consumers to the Internet. When it comes to smartphones, as we have said repeatedly, Windows Phone is our smartphone platform of choice. We are confident in our efforts to build a joint ecosystem with Microsoft, and we are aggressively executing that strategy with operators, retailers, developers and other stakeholders.