If you buy an iPhone 5 from Apple (AAPL), you won't get it for a good three weeks. And that is unacceptable.

The world's most valuable company is running into problems with its most important product. It can't make enough. Yes, demand is high, but there's more to the story. Apple's manufacturing partner, Foxconn, is having a bunch of production issues.

"The iPhone 5 is the most difficult device that Foxconn has ever assembled," an anonymous official at the company told The Wall Street Journal last month. "To make it light and thin, the design is very complicated."

Critics say the phone is absolutely amazing. "This is without a doubt the best iPhone yet," Engadget raves. "This is a hallmark of design. This is the one you've been waiting for."

And waiting for . . . and waiting for. A phone is not worth that wait. Not when plenty of competing phones built on Google's (GOOG) Android platform are available. Apple has a real problem on its hands -- one that could dent its revenue this holiday quarter. Apple sold more than 5 million iPhone 5 units in the first three days, but analysts were expecting as many as 10 million.

"We believe that sales could have potentially been much higher if not for supply constraints," William Power, an analyst with Baird Equity Research, wrote in a client note, according to Reuters.

So it's not that surprising to read rumors that Apple is basically moving full speed ahead with the next version of the iPhone, unofficially named the iPhone 5S. Digitimes reports that Apple is expected to begin production on a small batch of iPhone 5S phones in December, likely only 50,000 to 100,000 units.

"Facing low yield rates in the production of iPhone 5, Apple has accelerated the certification processes for related parts and components for the iPhone 5S," reports the Chinese-language Commercial Times, according to Digitimes. The Commercial Times also says the iPhone 5S will enter mass production in the first quarter of next year.

That timing would be highly extraordinary, since the iPhone 5 just launched in September. "If this new report from China turns out to be accurate, it could represent a dramatic shift in product release strategy for Apple, perhaps spurred on by increased competition from the likes of Samsung, and a raft of other Android-based smartphone competitors," PC Magazine writes.

What about this theory? The iPhone 5 is so tough to make, forcing the normally reliable Foxconn into hardware scratches and other production issues, that Apple is essentially moving on to the next version, which it will ensure has none of those problems.

Of course, this could all be an empty rumor. Digitimes is not known for its sterling accuracy. But even a rumor could hurt Apple's bottom line. If enough people think a new iPhone 5S is coming out early next year, then current sales of the iPhone 5 will take a hit. Rumors have dinged Apple's revenue plenty in the past.

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