Apple’s recent quarterly earnings reports have read as an incredible success story documenting the iPhone’s meteoric rise as a profit leading mobile device. In the last quarter alone, Apple sold 20.3 million iPhones including the iPhone 4 and iPhone 3GS.

Now Apple could be poised to sell as many as 30 million iPhones in Q4, reports John Paczkowski of All Things D. The report is based on an esitmate by BTIG analyst Walter Piecyk, who says that if Apple’s device continues its traditional growth, it could very well hit a record high in the next quarter.

The numbers are based on the Piecyk’s aggressive estimates in a note to clients that surpass the official 21.3 million iPhones that BTIG predicts for Q4. Piecyk says that the estimate is contingent upon a very good quarter for Apple, as well as a couple of other factors.

Traditionally, the US market, including AT&T and now Verizon, has accounted for 30% of global sales. In their latest quarterlies, AT&T said it had activated 3.6 million iPhones and Verizon said that it had added 2.3m, bringing the total to about 5.9m, or 30% of the 20.3 million sold worldwide.

If AT&T contributes an estimated 5 million sales and the newly inducted Verizon manages to sell at least 4 million, that would only leave a spare million on the table. Piecyk suggests that this million could come from the introduction of the iPhone on Sprint, whose CDMA network could accomodate the Verizon iPhone’s hardware with some simple tweaks.

Casually predicting sales based on the addition of another whole carrier seems a bit too aggressive in my opinion, but an estimate of 4 million in sales for Verizon is relatively low. We will see a stronger parity of sales between the two carriers, which could bring the US totals up to the 10 million mark.

The possibility of reaching these numbers would be bolstered by the fact that AT&T has an estimated 23 million iPhone users who could potentially be looking for an upgrade after an unusually long 18-month product cycle. In addition, keeping the iPhone 4 on as a lower priced $49 model on Verizon and AT&T could help beef up sales to the lower end of the market.

If the US sales hit the 10 million mark, and it continues the trend of totalling about 30% of global sales, a 30-million-iPhone quarter would easily be within reach. Even if Apple doesn’t sell 30 million worldwide in Q4, however, you can bet that it will be selling an absolute ton of them in the US as a new iPhone model becomes available on two carriers for the first time ever.