Forget about the iPhone. If Facebook gets its way, it could become the next purveyor of the world’s hottest phone. At least that’s according to TechCrunch, a technology blog that published a story suggesting that Facebook is building a mobile phone, or possibly teaming up with a hardware manufacturer to create a device that would leverage its social-networking software.

Facebook is denying the story but CNET has confirmed that the social-networking giant has reached out to hardware manufacturers and carriers seeking input on a potential Facebook-branded phone.

Such a device could cause ripples in today’s heated phone wars. Imagine a device manufactured by a third party such as Samsung or HTC, boasting an Android operating system, deeply integrated with Facebook’s social-networking features, and running on a carrier such as AT&T.

Yet if Facebook is creating a phone, the company would be wise to look long and hard at Google’s Nexus One. Google’s flagship smartphone is manufactured by HTC and uses the Android open source mobile operating system. Launched in January, the phone lets users transcribe voice to text and take advantage of GPS guided turn-by-turn voice directions to drivers. But it’s been a bumpy ride. The phone was sold via Google's website, for $529 without a plan or contract, or a subsidized $179 when purchased with a T-Mobile two year contract. However, in May Google announced that the online store would close, and the phone would be offered in retail stores. And according to Flurry Analytics, Google’s Nexus One sold around 135,000 units in 74 days – the same amount of time it took the iPhone to reach the one-million mark.

And then there was Microsoft’s Kin – the multi-million dollar effort to create a line of social phones. Rumors swirled that only 500 were sold and just six weeks after its launch, Microsoft put an end to the product line.

All the more reason for Facebook to tread carefully in today’s challenging mobile phone market.