Late last year, we reported on Canonical's plans to bring their desktop Linux distribution, Ubuntu, to mobile devices and smartphones. When Ubuntu for Android was released in February, most assumed that it was the result of these plans, even though it was a webtop application and not a full on smartphone operating system. However, Canonical has just posted a job opening that suggest that a true "Mobile Ubuntu" may not be entirely out of the question after all.
The posting calls for a "Business Development Manager (Ubuntu Phone OS)," which certainly sounds to me like they are preparing their own operating system, much like MeeGo, Boot2Gecko, or even Android as a full smartphone OS. Not only that, the posting also discusses the "launch of Ubuntu as a smartphone operating system." With this, it seems even more clear that we may see Ubuntu launch a complete OS, not just a docked version used with video out.
Of course, the Linux mobile operating system has been tried before, and the results weren't great. MeeGo was killed off by Nokia in favor of Windows Phone, and although cool, Boot2Gecko doesn't really seem to be going anywhere. Android is based of the Linux kernel, but is hardly a true "open" OS, and functions quite differently than something like mobile Ubuntu would.
Still, Ubuntu is the third most popular desktop OS, and by far the most popular Linux OS, so perhaps with such strong backing a Ubuntu smartphone operating system could become a reality.