Two prototypes of the planned fourth-generation iPhone have now leaked out, and that is not counting the white front panel believed to belong to the next iPhone that surfaced in Taiwan last week.

The prototypes, obtained by a California-based tech site in April and a mobile accessories dealer in Vietnam earlier this month, were full units. In each case, those in possession of the phones–both believed to be authentic–disassembled the devices.

And in each case they found no evidence that the next iPhone will support Near Field Communication.

Of course, they were not specifically looking for NFC, but one expert told me evidence of the short-range wireless technology probably would have been hard to miss. That is especially true if the NFC antenna was embedded in the touch screen, as at least one patent application from Apple indicated it would be.

Even without the leaked prototypes, NFC market watchers see it as less and less likely that this year’s iPhone will pack the technology.

With only a month or so to go before the release of the new iPhone, more would have slipped out from component suppliers by now, they said. But so far, chip and middleware suppliers have remained silent. No tidbits have escaped the NFC and contactless test houses, either. Despite Apple’s vaunted reputation for keeping its vendors quiet, more stray boasts of supply contracts for the high-profile smartphone likely would have circulated around the industry by now.

If, indeed, the next version of the iPhone ships without NFC onboard, it will be a disappointment to NFC-industry backers, who have followed with much anticipation the steady stream of patent applications filed by Apple and published by the U.S. Patent and Trademarks Office in recent months. The patent claims give NFC a prominent role, placing it and the iPhone squarely at the hub of device-sharing networks, the retail payment experience and event ticketing, as well as peer-to-peer funds transfers.

There were also reports of very early iPhone prototypes produced by Apple supporting NFC, along with sightings of Apple execs wandering around at least one big smart card trade fair late last year. All this, especially the patent claims, shows Apple is serious about NFC, and most observers believe if the technology is not in the next version of the iPhone, it will certainly be present in the fifth generation, likely to hit the market in mid-2011.

While an NFC-enabled iPhone has been called a game-changing event for the NFC and contactless-mobile markets, a snub this year by Apple probably will not slow the momentum of the technology or the schedule for models likely now in the pipeline to hit store shelves by early 2011. 

Such tier-one handset makers as Samsung, Nokia and LG are said to be producing more models in response to renewed demand from mobile operators. Chip maker NXP Semiconductors is again circulating rosy projections internally for NFC chip shipments. And work continues on Android-based smartphones supporting the technology, said sources. There are also NFC or contactless iPhone peripherals coming to market.

Still, as I’ve said before, with the technogentsia having anointed Apple boss Steve Jobs a genius, his blessing of NFC would prompt other handset makers to accelerate their plans for incorporating the technology in their product lines. More developers would get to work on NFC-based services for the App Store, too.

The new iPhone sans NFC would give Nokia a chance to recapture the initiative on NFC and for producers of Android phones and BlackBerrys to introduce a prominent feature that Apple doesn’t have.

But there is nothing like the buzz that would be created for NFC if Apple endorses the technology. Yet, that will likely have to wait until next year.