An iPhone 5 prototype lost in a San Francisco bar has offered hints to the release date of the next iteration of Apple's flagship device.

This is the second time that an iPhone prototype went missing in a bar just before its release. But in April 2010 Apple was successful in getting the iPhone 4 prototype back after it had been sold by a finder.

This time Apple is having a tough time getting back its iPhone 5, which was left in a Mexican restaurant in San Francisco and then was sold on Craiglist for $200, according to reports.

CNET reports that Apple has contacted the San Francisco police and via location tracking eventually tracked the phone to a single-family home in San Francisco’s Bernal Heights area, but the resident has denied any connection to the event.

Analysts and reporters are suspicious of the iPhone prototype loss and speculating that Apple is doing it deliberately.

Meanwhile, according to speculation, if the iPhone 5 prototype has been given a trial run then surely the release date is round the corner, possibly in weeks. Rumors suggest that the phone might be launched either in September or October.

Apple is due to release the next iteration this fall, but analysts are expecting only an iPhone 4S in the fall and iPhone 5 with a materially revamped user interface in 2012.

Take a look at the most-rumored iPhone 5 features:

Apple's iPhone 5 is expected to boast of significant hardware and software upgrades, along with an 8-megapixel dual-LED flash camera and A5 dual-core processor found in the iPad 2 to give stiff competition to other dual-core smartphones found in the market today.

Apple is rumored to increase the screen size of iPhone 5 to compete with Android smartphones, probably going for a bigger edge-to-edge 4-inch curved glass screen, compared to the current iPhone 4 screen of 3.5-inch with multi-touch display.

Apple iPhone 5 is expected to support near field communication (NFC). But Bernstein Research analyst Toni Sacconaghi cited that Apple will not adopt the NFC-based mobile payment feature in the upcoming iPhone 5 until Apple is convinced that the technology's chicken-and-egg-problem is solved, as the NFC requires widespread consumer adoption and critical mass with merchants.

NFC technology can transform the device into a convenient way for payment and device communication. NFC has potential for more than just money transaction. The technology could offer features that allow multiple mobile devices to sync for speedier information exchange and gaming.

The iPhone 4 runs on 1GHz ARM Cortex-A8 processor, and the iPhone 5 is rumored to sport a 1.2-1.5 GHz dual-core A5 processor with probably a 1GB RAM.

While the A5 dual-core chipset can challenge the Samsung Galaxy S 2 and other NVIDIA Tegra 2 chip-based Android phones, it cannot match the power of dual-core 1.5GHz chipsets.

An earlier report said Taiwan SemiConductor Manufacturing Company (TSMC) had started trial production of the Apple A6 line of processors. It is reported that the TSMC manufactured A6 chipset will incorporate 3D IC technology.

It has also been reported that TSMC is in production with 3D IC technology and is in a race with Intel to manufacture a 3D IC chip. EETimes reported that TSMC could deliver processors with 3-D interconnet by the end of 2011.

If that report is true, Apple could further delay the iPhone 5 launch as it places a faster A6 chipset in the upcoming iPhone. Recently, Computerworld reported that certain Taiwanese suppliers of Apple claim they are starting the production of 25 million iPhone 5 units that would be delivered in the second half of this year, essentially confirming a December release.

And a few analysts predict that the other features of iPhone 5 will most probably remain the same with minor tweaks, also it will most probably come without 4G and LTE support.

Amid rampant speculation in the blogosphere, it is anticipated that the next iPhone could come as a world phone, compatible with both GSM and CDMA. It is also believed that the phone will feature a SIM-less design, including up to three to four internal antennas. It is expected the iPhone 5 will have 16/32/64 GB internal storage.

Apple certainly knows how to surprise and already has a few things in place like iCloud which can steal the thunder from Android devices. Apple's iPhone features are extensively varied from Android smartphones, which means the loyal Apple fan base remains the same.