Citing unnamed “people familiar with the situation,” AppleInsider’s Kasper Jade ticks off a schedule of release for a batch of new iPods, overhauled notebooks and refreshed iMacs, confirming several rumors that have been floating around for weeks and adding a few of his own.

Taken alone, none of these announcements sound quite big enough to account for the sharp drop in the company’s gross margins — from 34.1% to 31.5% — CFO Peter Oppenheimer warned analysts to expect this quarter, citing a mysterious “future product transition.” But together, they might do the trick.

Here they are, in the order Jade expects them to be released:

• 
  New iPods in September. Digg founder Kevin Rose, an Apple watcher with a track record considerably more checkered than Jade’s, predicted last Friday that Apple would soon revamp its entire iPod line, cutting prices sharply, making cosmetic changes to the iPod touch and introducing a significantly redesigned iPod nano with a long thin screen (link). Over the weekend Rose specified a date on which all this would occur: September 9 (link). Without endorsing that particular Tuesday as the date, Jade’s sources confirm that Steve Jobs himself will headline a special event tentatively scheduled for the second week of September in which “cheaper and slightly modified iPod touches players and new iPod nanos and related service announcements are expected to take center stage.” (link) One thing that will not be announced at that event, according to Jade’s sources, is the long-rumored Newton-like handheld multi-touch device.
• 
  New MacBooks and MacBook Pros in September or October. Jade’s sources are cagey about the timing here, but they were explicit in saying that new versions of Apple’s hot-selling notebook computers would not be available until some time after the new iPods are introduced. Whether that means they are announced at a separate event — perhaps in October — or whether they will be announced at the same event and shipped some weeks later is one of those mysteries that may not get cleared up until the event actually occurs. Among the changes expected: a MacBook clad in aluminum (like the Pro) rather than plastic; tapering around the edges (a la MacBook Air) to produce a slimming effect; a mysterious new chipset (but still with an Intel (INTC) CPU); and a newly designed battery cover and latch that offer easier access to the hard drive.
• Refreshed 20-inch and 24-inch iMacs in November. This is a brand new rumor, rather than a rumor confirming old rumors. According to Jade:
  • “People familiar with these plans have described the refresh to consist of ‘speed bumps’ rather than major internal or external changes. Based on the roadmap presented to AppleInsider, these systems would debut later this fall following the release of the new MacBooks, making their way to market with little fanfare.”

Not expected before the end of the year are refreshes of the Mac Pro or the Mac mini, although Jade’s sources report that the latter, once given up for dead, is getting a “major overhaul — the most significant in the mini’s short history.”

[Timeline and photos courtesy of AppleInsider.]