By Katie Marsal

Published: 12:00 PM EST

Apple Inc. has placed the blame for missing its self-imposed Leopard release date on its itty-bitty iPhone device, but analysts on Wall Street suspect other culprits -- such as a widely touted but so far elusive set of "top secret" features destined for the next-generation Mac OS.

"While Apple cited a shift in resources to iPhone and more time for developers to beta test as reasons for the delay, our analysis indicates that if not for the 'secret' features, the core Leopard operating system would likely have shipped on time," American Technology Research analyst Shaw Wu told clients on Friday. "We believe the extra time Apple is allocating is for developers to test secret features that will likely be revealed at its WWDC 2007 conference starting on June 11, 2007."

Gene Munster, a Sr. Analyst over at PiperJaffray, was similarly suspect of Apple's explanation, but chose to note the irony of the situation as it relates to rival Microsoft Corp. rather than point the finger at any one Apple initiative. "While we are not convinced the delay is entirely related to the iPhone, the important part is we believe Apple's product development remains robust, and the iPhone, Leopard, and other new products (announced in June) are coming," he wrote in a note to Apple investors. "Despite the PR black-eye Apple will get from delaying Leopard (given Apple routinely chastises Microsoft for product delays), the announcement included that Apple will release the iPhone on time in June."

Acknowledging that there are few certainties when it comes to specific release dates for high-profile Apple products, Munster said he sees the company's statement, while disappointing on the Leopard front, as a likely means of boosting confidence in a June arrival of the iPhone. "Apples track record at getting hardware out on time is hit or miss, as evidence by the recent one month slip of Apple TV," he said. "Apple's statement specified late June as the launch date of the iPhone, but Apple may deliver it earlier at the Worldwide Developers Conference, which begins on June 11."

Unlike Wu, who recently told clients that some prospective Mac buyers had already begun withholding their new computer purchases in anticipation of Leopard, Munster said he has observed "little-to-no delay" in that regard. In his note to clients, the PiperJaffray analyst said he believes Leopard is poised to serve as a catalyst for Mac sales whenever Apple gets around to shipping it. For the meantime, he's shifted an estimated 8 cents in earnings-per-share (or 2.6 percent) from the June '07 and Sept. '07 quarters into the Dec. '07 and March '08 quarters.

For his part, Wu said his recent reduction in near-term Mac assumptions already reflects the risk exposed by Leopard's delay. "We believe consensus sell-side estimates continue to be unsurprisingly aggressive and need to reset closer to ours," he told clients. "We view this delay in Leopard and reset in sell-side estimates as short-term issues. We see worst case downside risk to $80-85."