Are you sitting down?  For the second time in as many years, it’s been reported that an Apple employee misplaced a prototype of its newest iPhone in a San Francisco-area bar.

Are you sitting down in Cava 22, a Mexican restaurant in San Francisco’s Mission district? That’s where CNET says “the errant iPhone” made off without its owner in late July, setting off a scramble by Apple security to recover it.  CNET cites “a source familiar with the investigation.”

Apple — very friendly — just returned a message we left to say, “I’m afraid we don’t have anything.” They did promise to call again and let us know they really do have a new iPhone 5 to show off.

Depending on whose rumor you believe, the iPhone 5 will be released in early October; customers of Verizon Wireless, AT&T and, for the first time, Sprint, will be able to have it.

CNET reports on Apple’s efforts to get the prototype back:

“Apple electronically traced the phone to a two-floor, single-family home in San Francisco’s Bernal Heights neighborhood, according to the source. When San Francisco police and Apple’s investigators visited the house, they spoke with a man in his twenties who acknowledged being at Cava 22 on the night the device went missing. But he denied knowing anything about the phone. The man gave police permission to search the house, and they found nothing, the source said.”

If all this sounds familiar, it should. Last year a prototype iPhone 4 was left behind at a Bay-area bar, and the company got it back — but not before the website Gizmodo had bought it for $5,000, thoroughly dissected it and reported the details. The legal wranglings over that just recently ended; Gizmodo and its then-editor, Jason Chen, were not prosecuted for possession of stolen property, though the young man who picked it up off the counter did face lesser charges.

If you’re not someone who salivates over every hint of a new iPhone, well, we’ve reported before on the small cottage industry that’s built up over Apple rumors (some of the more industrious websites include MacRumors.com and 9to5Mac.com). Here’s a picture 9to5Mac sent us in July, which they said they believed was of an Apple employee holding a prototype on a train. This time there were no leaked details.

The new phone, if you believe what they’re saying … will have a rounded back … a larger screen… won’t disconnect calls if you touch the edges … will fly — well, it won’t fly, but the rumors do.