Google never said much about the acquisition or its plans for Rubin, but he’s been on the company’s payroll ever since, presumably holed up somewhere on its campus in Mountain View, Calif., working on something–perhaps with the “graphics-software fanatics” from Skia, another mysterious mobile start-up Google acquired in 2005. Together they’d make quite a team–Rubin with his passion for location-aware mobile devices and Skia’s engineers with theirs for the robust, but portable, graphics engines that could be used in them. Theoretically, of course.

Why the history lesson? Well, industry sources tell The Wall Street Journal that Google might publicly detail its long-rumored mobile-phone project as early as Monday. “U.S. carriers likely to be part of the announcement are T-Mobile and Sprint, according to our sources, but there could be others by the time Google says its piece,” the Journal reports. “While Sprint appears to be agreeing to work with Google to put the Web giant’s new Linux-based open operating system into phones, T-Mobile will probably go even further: the company has worked with Google for months on plans to build Google-powered phones with a variety of Google software and applications. As far as handset partners for Google, Taiwan’s HTC is a likely bet, our sources say. Samsung, LG and Sony Ericsson are also possible, but we’ll wait and see the full roster. Equally interesting will be who isn’t on the list.”

Indeed. Because whoever’s not on that list could be losing out on a chance to become a true player in the mobile-search advertising business, which research outfit the Kelsey Group recently claimed will grow to $1.4 billion in 2012 from $33.2 million this year–in the United States alone.

Given Google’s well-documented efforts to set up a free Wi-Fi network in San Francisco, we believe the upcoming spectrum auctions could represent a rare opportunity for the company to acquire something resembling an exclusive (licensed) nationwide WiMax footprint, and largely eliminate any access dependency on third parties. As such, we believe Google’s potential involvement bears watching, especially in light of the fact the company has shown little hesitation in delving into the other aspects of networking. Google’s selection of equipment vendors, such as Force10 and Infinera, indicate to us a willingness to embrace leading-edge technologies, and we believe WiMax fits that description.”

–Joe Chiasson, Susquehanna Financial Group, February 2006

This morning Google announced an alliance with Sprint Nextel that will see the two companies working together to bring Google’s search, digital mapping technologies and GTalk chat service to Sprint’s WiMax network, which, once it’s completed, will theoretically allow wireless Web access at speeds and prices similar to cable connections.

The deal follows the announcement of Sprint’s plans to collaborate with Clearwire to build out a nationwide WiMax network by the end of 2008. It also follows Google’s conditional pledge to drop at least $4.6 billion on the Federal Communications Commission’s auction of the 700-megahertz spectrum, which has long been said to be the future of WiMax (with fewer line-of-sight issues and wider coverage and better building penetration).

Coincidence? Or part of a master plan in which Google wins the 700-megahertz spectrum, uses it to help complete the Sprint/Clearwire nationwide WiMax network effort and then announces the long-rumored Google Phone–upending the telco-cable duopoly in the process?