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In just two days, Apple (Nasdaq: AAPL) will unveil the iPhone 5 to the world. This we know. That device will of course be the day's main event, but that's probably not all that investors and consumers will be treated to. We already know five things the Mac maker won't say on Wednesday, but what else mightit unveil?

iPods. Lots of iPods.
Historically, Apple has used a September press event to unveil new iPods, so it makes sense for this product family to get upgraded alongside the iPhone.

With the iPhone 5 expected to increase its screen size to a 4-inch display, up from the current 3.5-inch one, the iPod Touch will also probably get a similar treatment. Since the iPod Touch has always been just an iPhone without the phone, if the iPhone gets a boost in screen dimensions, so should the iPod Touch.

That would make the transition to 4-inch displays a unified move, instead of upgrading the iPhone display and leaving the iPod Touch untouched. Last year, the iPod Touch was somewhat neglected and didn't receive any upgrades, assuming you don't consider the addition of a white model an upgrade. These devices are also rumored to be getting a redesign and use in-cell touch display technology that enables them to become even thinner.

Source: Apple. Current iPod family.

9to5Mac also reports that the iPod Shuffle may get some minor tweaks, while the iPod Nano might get redesigned to a taller form factor as in previous generations.

As a whole, the iPod family really isn't important financially for Apple anymore, at just 4% of trailing-12-month sales. Sales have been on a steady decline for years as a planned victim of iPhone cannibalization, but the iPod's significance lies in holding down the music-player fort, as it still retains a roughly 70% market share, even more than a decade after its introduction.

They're also important for branding, as iPod is nearly synonymous with Apple, and it was the first breakthrough product during Apple's resurrection. iPods also serve important strategic purposes, drawing young consumers into the ecosystem before parents are ready to buy their kids a smartphone.

The iPod may not get as much attention as it used to, but it will probably never suffer the same fate as Microsoft's (Nasdaq: MSFT) Zune: a quiet death.

iOS 6
Apple unveiled the next major version of its mobile operating system, iOS 6, in June at its Worldwide Developers Conference, with a purposefully vague release timeframe of "this fall." The software will clearly debut alongside the new hardware.

Source: Apple.

This version will include some very significant changes, such as ditching Google (Nasdaq: GOOG) Maps in favor of the in-house mapping service Apple has spent years building, direct Facebook (Nasdaq: FB) integration to complement Twitter for requisite social features, additional Siri functionalities, and the new Passbook app that will eventually help turn iPhones into bona fide digital wallets.

Apple also continues to add features specifically geared toward the Chinese market, including integration of local dominant search engine Baidu (Nasdaq: BIDU), which is an important win for the "Google of China" in preventing Google from becoming the "Google of China."

The iPhone 5 will ship with iOS 6 preinstalled and should be released as a software update for compatible devices around the same time. Expect an official date on Wednesday.

Slim chances: Macs or iPad Mini
There have been recent reports that production of 13-inch MacBook Pros with Retina displays is now ramping up and that the displays themselves had entered manufacturing last month. Oddly, an unusual suspect in the Apple rumor mill, Fox News, suggested that upgraded iMacs are "imminent," although these devices won't feature a Retina display yet.

Of course, investors are now expecting an iPad Mini to do battle with Amazon.com's updated Kindle Fire lineup and Google's Nexus 7, but Apple is supposedly planning an October event for the smaller version.

My guess is that the company hosts an event next month for all of these aforementioned long shots, while this week's event will focus on updating the iPhone and iPod lineups.

Is it Wednesday yet?
For Apple investors, Wednesday can't get here soon enough. In the meantime, peruse this iPhone 5 report that's included in our premium Apple research service to make sure you're up to speed before the unveiling. Sign up today and get a comprehensive report on about Apple, an iPhone 5 report, and regular updates!