Apple appears to be bucking its reliable release schedule for hardware and software. Monday, reports from the well-sourced site The Loop and others indicated that the company would likely delay its release of the iPhone 5. Sure enough, Apple’s announcement about its Worldwide Developers Conference promises a peek at iOS and OSX, but mentions nothing about an iPhone.

Why would Apple delay the next iPhone? There were a couple of theories floating around Tuesday morning.

By not releasing the iPhone 5, the company will have the time to make the handset compatible with LTE networks. Apple took its time getting to 3G, but there are an increasing number of LTE-capable Android phones on the market. Plus, mobile companies are building out their LTE networks, so a delayed release means a more expansive network.

Another theory is that Apple is saving everything for a huge fall event. Not everyone is on board with that idea. SlashGear theorized that Apple could be waiting to release the iPhone 5 until the holiday season. Over at 9 to 5 Mac, they’re reporting that the Japanese site Macotakara says that production on the iPhone won’t even start until late 2011, putting a release in 2012. (It pays to be wary of production rumors, but it wouldn’t quite be a roundup without one, would it?)

Still,reports Monday said that iOS 5 , with a cloud music service, would likely debut in the fall. Those reports also said that the latest version of Apple’s mobile platform might launch along with a third iPad. Could Apple be waiting to release all three products at once?

Releases of the Verizon iPhone, the iPad 2 and the ever-rumored white iPhone spring release have been cluttering up Apple’s calender, and the company could be trying to avoid Apple overload.

Not that Apple needs help in the publicity department. Despite the rumors that there will be no iPhone 5 at this year’s WWDC, tickets to the annual event sold out in less than 12 hours.

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