Microsoft Gearing Up for BlackBerry-Maker Takeover?

How’s this for a pairing: Microsoft Corp. (MSFT) and BlackBerry maker Research in Motion (RIMM)?

That’s the latest rumor in the lead-up to next week’s behemoth Mobile World Congress trade show in Barcelona, where sources say Microsoft CEO Steve Ballmer will hold a press conference on the latest version of Windows Mobile 7.

Insiders also speculate we’ll hear – or perhaps it’s more like they’re gleefully awaiting – the announcement of a RIM acquisition. All Things Digital says its Microsoft sources say Ballmer is wide open to the idea. (Interestingly, they say he has no interest in Palm.)

Buying RIM, maker of the ever-popular BlackBerry mobile device, could be a solid move for Microsoft, which is falling behind in the smartphone operating system wars. Rivals Google Inc. (GOOG) and Apple Inc. (AAPL) are far ahead of the Bill Gates-founded software giant.

And while Microsoft undoubtedly holds a bigger war chest than RIM, its stock price is about a third of the BlackBerry creator’s. Microsoft shares have hovered around the $28 mark, while RIM’s is in the upper-$60 range.