Ars Technica is reporting that developers are leaving no stones unturned inside the new iPhone OS 3.0 beta, stumbling upon clues as to what Apple is working on lately. One developer, the site claims, has discovered a file with references to two new iPhone models, one fresh iPod touch model (possibly), and two products simply referred to as "iProd" and "iFPGA," respectively.

According to ars details about the USB configuration of the various iPhone and iPod touch models, as well as the device ID and product names, are listed in the file /System/Library/AppleUSBDevice/USBDeviceConfiguration.plist. The tech-focused site explains that the same file in iPhone OS 2.2.1 lists the original iPhone, iPhone 3G, and first- and second-gen iPod touches, referred to as iPhone1,1; iPhone1,2; iPod1,1; and iPod2,1, respectively. An unknown iPhone model, labeled iPhone2,1, which started turning up in web server logs as far back as October 2008, is also listed in the file.

However, in addition to these references, which are also included with iPhone OS 3.0 beta, USBDeviceConfiguration.plist in the new software contains references to iPhone3,1; iPod3,1; iFPGA; and iProd0,1, ars reports. “All of the products are assigned unique productID numbers, though all are assigned a productString of iPhone. These details are reported to Mac OS X when the devices are plugged in via USB, and would show up in System Profiler, for instance,” the site explains.

Noteworthy is ars' conviction that iPhone3,1 and iPod3,1 are clear references to next-gen hardware versions of those products, also citing its source as saying that the iFPGA could be a prototype device that uses field-programmable gate arrays (a type of programmable microchip).

Courtesy of 9to5Mac, the new codes, as well as the old ones are listed as such:

New codes:

iPhone2,1 - 0×1294
iProd0,1 - 0×1295
iPod2,2 - 0×1296
iPhone3,1 - 0×1297
iFPGA - 0×1298
iPod3,1 - 0×1299″

Old codes:

iPhone First Gen - 0×1290
iPod touch 1G - 0×1291
iPhone 3G - 0×1292
iPod touch 2G - 0×1293.