????By Philip Elmer-DeWitt

????Adding his voice to the drumbeat of speculation about Apple’s (AAPL) future iPhone plans, Kaufman Bros.’ Shaw Wu weighed in early Wednesday with a new report from his supply chain and industry sources.

????Among his findings:

• Two out of three. Wu had heard that there are three new iPhones in the works, but based on clues that developers are finding in the beta iPhone 3.0 software, he now believes “only two will see the light of day.”

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• iPhone Sr. and iPhone Jr. Wu hears that one of the new iPhones will have longer battery life and a much more powerful processor capable of running more complex apps. The other would be a less-powerful “junior” iPhone.

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• Millions of iPhones. Wu’s sources indicate a “build plan” for the new models in the 5 million to 6 million unit range, considerably higher than his current 4.5 million estimate for the September quarter (fiscal Q4).

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• Timing is critical. Wu is still not sure whether the new iPhones will ship in June or July. If the latter, the June quarter could be a tough one for Apple. Wu was expecting Apple to sell 3.2 million iPhones in the March quarter (fQ2) and 3.7 million in the June quarter (fQ3). But all bets are off if the new iPhones don’t arrive until late June or July, and customers who were thinking about buying the current model hold out for the new ones.

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• AT&T may cave. Wu’s sources indicate a “high likelihood” that AT&T (T) will come out with more flexible “tiered” data plans to replace the one-size-fits-all $30 a month unlimited plan that has run into resistance among newly price-conscious consumers.

????Although Wu maintains a “buy” rating on Apple with a $120 price target, he pulled it off Kaufman’s special “focus list” last month as its share price began to close in on his target. The risk-reward is “less compelling” now, he writes, “than when the stock was in the $80-$90 range.”