Speculation has been rampant about the introduction of a sub-$100 iPhone. Many thought this would come with the device’s introduction to Wal-Mart stores. That proved untrue, however, with Wal-Mart offering a mere $2 savings from the price tag in Apple and AT&T stores.

I still believe we’ll see an iPhone or iPhone-like copycat for less than $100 this year. Already, Apple is selling refurbished iPhones for $99. The shape and size of a cheaper iPhone joins the perennial Apple product guessing game that ebbs and flows around upcoming Macworld expos (next week).

The latest comes from Friedman Billings Ramsey & Co., which projects an “iPhone nano” that will be a stripped down version of the iPhone with only phone and iPod features (sans data plan). The applications and Web browser are at the heart of the iPhone’s appeal in my opinion so this may not be the form the speculated device will take.

But one thing is for sure: Apple will transition to cheaper chipsets from Qualcomm, replacing those it currently gets from Infineon Technologies. This could be supportive of claims of a new cheaper iPhone on the horizon. Furthermore, if history is any indication, the rapid-fire introductions of new iPod models over the past eight years could support claims of a forthcoming release.