iPhone 5 (black, left angled, display 001)

With last month’s trial production and this month’s ramp-up underway, all checks now point to Apple having finalized the next iPhone and now mass producing the device, in time for a presumed Fall launch.

A Chinese website behind alleged iPhone 5S production shots is adamant the iPhone 5S has the same four-inch display as its predecessor.

That may not be the case: if a Taiwanese newspaper is to be trusted, Apple has increased the iPhone 5S’s screen to measure 4.3 inches diagonally. Worse, the move, the story goes, may delay the handset’s introduction until the end of the year…

Bloomberg relayed a report by the Taiwan-based Commercial Times newspaper citing unidentified people in the semiconductor industry as confirming Apple originally targeted a September or October iPhone 5S unveiling.

Another factor behind the iPhone 5S delay: Taiwan Semiconductor Manufacturing Co. (TSMC) may not be able to deliver the chips until August, according the the report.

The story is in line with DigiTimes, another Taiwanese trade publication which on Monday cautioned that yield issues with the fingerprint sensor and colorized casing had pushed back the iPhone 5S.

In iDB’s own non-scientific poll, 1 out of each 5 respondents voted for a 4.3-inch iPhone.

Increasing the screen size would inevitably entail redesigning the handset around a larger form-factor. That said, I doubt The Commercial Times is necessarily taking about the iPhone 5S here as several analysts have speculated that Apple could release multiple iPhones this year.

iphone 6 concept 3
4.3-inch iPhone 6 concept by ADR Studio.

In addition to the “regular” iPhone 5S, analysts have called for a rumored budget iPhone and another high-end model featuring a large screen, with dimensions ranging from 4.3 to 4.8 inches and beyond (depending on whom you ask).

Speaking of the less-pricey iPhone, Commercial Times is expecting the mid-tier device by the end of the third quarter. The notion echoes AllThingsD from yesterday, which confirmed Apple’s July iPhone 5S production ramp-up. Curiously enough, AllThingsD hasn’t ruled out the possibility of a second, lower-cost iPhone version later in the year.

Apple for sure can get away with another S-upgrade, but not at the expense of the lucrative holiday season. I just can’t imagine Tim Cook & Co. risking further profit erosion by not having a new iPhone on sale in time for the beginning of the all-important holiday shopping fever.