Unless you’ve been living under a rock for the past few months, you are probably well aware that tomorrow, Wednesday January 27th, Apple is hosting one of its infamous “Events” and the centerpiece will be a tablet-like iDevice which was, coincidentally, just “confirmed” by the CEO of publisher McGraw-Hill on CNBC minutes before this post was sent to the presses.

The big questions are, what will it be like? What sort of tech specs will be under the hood? Based on years of following the Tablet’s development through our sources in Cupertino and backed up by grapevine consensus, here’s what we’re expecting at the heart of tomorrow’s announcements.

First, the bullet point tech specs:

• 10-inch touchscreen display with one of the highest resolutions ever produced, and almost certainly in a 16:9 aspect ratio. A smaller, lower-cost approx. 7 inch version has been widely speculated upon and we’ve heard tell of prototypes in this size range but the most reliable reporting we’ve received has focused on the 10-inch design. As for resolutions, many internal Apple documents specified a desire to support 720P HD video–suggesting something in the range of 1280×720 or 1366×768.
• At the heart of the new iDevice will be a hardware platform fundamentally similar to the iPhone/iPod Touch but considerably scaled up. Some prototypes contained ARM Cortex A9 MPCore CPUs with dual cores running at 2GHz+ for performance many times that of the iPhone 3GS (single core Cortex A8 at 600MHz with a tiny fraction of the on-chip L1/L2 RAM cache of an A9 MPcore). The shipping hardware could be a bit more modest in clock speed, and might even be single-core, but will almost certainly be from the Cortex A9 family.
• Many have debated whether the Tablet will run Mac OS X or iPhone OS, but this is based on the fallacy that the two are separate. In fact they are both based on the XNU kernel and Darwin core OS. So while we foresee what could best be described as a variant of the iPhone OS (4.0?), it will also cross over into many areas previously exclusive to Macs such as multitasking and “windowed” interface elements. New input methods (see below) will also make this unique OS X variant an entirely new animal in many ways.
• The Tablet’s SoC will include a graphics core based on PowerVR’s SGX Series5-XT GPU — from the same family as the graphics processors in the 3GS and latest iPod Touch, but scaled up immensely with far more rendering pipelines to provide several times the performance of the SGX 520 in current iDevices as well as full support for OpenCL, Apple’s GPU-coprocessing technology.
• System RAM (DDR2 rather than the DDR1 in iPhone/iPod) will be in the range of 1GB, possibly 2GB in a high-end model.
• Onboard storage will be provided by high-performance Flash drives somewhat larger and far faster than those in hand-held iDevices.
• Built-in speakers will be modest, but among the best in any device this size and will be full stereo unlike the single speaker in hand-held iDevices.
• A new variant of the venerable iSight will also be included, enabling much more than mere videoconferencing and taking self-shot pictures for DailyMugshot (see below).
• Networking will be provided by 802.11n Wi-Fi and a 3G cellular data chip (4G capability has been demonstrated in prototypes but probably won’t ship until a second generation 6-9 months from now). Most likely, a less expensive model with Wi-Fi only will be available.
• Weight and thickness will be considerably less than a Macbook Air — probably similar or superior to that of Amazon’s Kindle DX e-reader: 1/3 of an inch thick and 19 ounces (just over a pound). Overall dimensions will be significantly smaller than the Kindle DX since there will be less margin around the display.
• On-board ports will likely include a micro USB port, stereo audio in/out, and the same 30-pin Apple docking port shared by all iDevices. If in accordance with prototypes there is a bundled or optional docking station, it’s possible that the onboard USB port will be eliminated in favor of one on the docking station. Built-in Bluetooth will also be included and will support several functionalities not currently possible with the iPhone OS including bluetooth keyboards, mice and wireless Sync. 802.11n will likely also be an option for faster wireless syncing.

What’s in a name? Despite the rabid speculation over which of the publicly known trademarks owned by Apple — including iSlate, MagicSlate, Canvas and iPad — we’ve been told more than once that those trademarks exist more for the purpose of covering Cupertino’s legal bases rather than necessarily being serious candidates for the Tablet’s final moniker. If we had to bet on one we’d pick MagicSlate or Canvas, but our money is on something entirely unpublished and unexpected.

As for input methods, this is one of the areas where the Tablet will be most innovative. Multi-Touch will be expanded upon, and a full-size onscreen keyboard will be complemented by voice as well as “drawn” input ala Newton thanks to a “pen-like input” patent filed by Fingerworks, the company Apple acquired some years ago to bolster its touch-input technology. Another project Apple has been working on aggressively is known internally as Air Gestures; in essence, a camera-driven interface allowing the user to rest the Tablet in their lap or on a vertical dock and manipulate on-screen objects by gesturing with their hands 1-3 feet from the Tablet’s iSight. This obviously doesn’t work well in a poorly lit environment, but has several advantages including not getting finger smudge-marks on the screen.

Apple has been working on smudge-resistant screen materials, but those technologies have their limits and the potential for developers to support an almost infinite number of custom gestures through this technology is huge.

Pricing will of course depend on exactly how many models (2-3 were specified in early roadmap documents, but these predated Steve Jobs’ return to work in September when many such decisions were finalized) are introduced and what their specs are, but $700 and $900 have been Infinite Loop’s price targets from day one according to reliable sources. “Under $1,000″ is a safe bet and if for some reason there were a single price point, we would anticipate that would it be well below that.

As for 3G cellular data services, we anticipate that there will be at least two providers available: AT&T and Verizon. T-Mobile is also a possibility, but talks between Apple and major domestic U.S. providers are ongoing which suggests that additional options may be available by the time the Tablet ships as well as added in the months following. There has been speculation as to whether an option will be available with at least one provider to pre-pay for service bundled into the cost of the device rather than by a monthly fee but our confidence level in this particular rumor is lukewarm at best.

Thanks to the ARM processor, it will be dead simple for anything from the App Store to run on the Tablet; developers will have at least two months to update their applications specifically for the Tablet, but a “compatibility mode” will scale up existing apps to full screen or run them in a roughly 3.5-inch 480×320 window if need be.

One of the biggest elements in the Tablet won’t be what it can do, but what it can deliver: content. More free and cheap (99c and $1.99 HD instead of $1.99 and $2.99 HD, with even steeper season ticket discounts) TV episodes on iTunes to better compete with streaming sites like Hulu, streaming/subscription options across all media, and major new deals with providers of other content such as newspapers, magazines, books et cetera. We’ll be looking at these in more detail later in this January Event Preview series.

There will be plenty of surprises tomorrow, given how intensely Infinite Loop has maintained the “cone of silence” — even when we’ve been fortunate enough to get exclusive information about Tablet-related projects, we have often been forced to keep them under embargo until they are leaked elsewhere, to protect our sources. And since few real public leaks have occurred, this has made covering the Tablet even more frustrating than what we experienced with the AppleTV or the iPhone. But our perfect track record of having never gotten a source in trouble over 15+ years in this business is far more important to us than the tally on our prediction scorecard.

If there’s anything we’ve overlooked in this detailed breakdown of Apple Tablet expectations, by all means send in your questions via Twitter (@MacOSRumors), email (rumors@macosrumors.com), AIM (MacOSRumors), or simply use the web comments form below. Stay tuned for several smaller installments in this Event Preview series, and for our Live Coverage/Discussion starting on Wednesday just before 1PM Eastern/10AM Pacific which you can follow here on the web or by following our Twitter feed — as well as ongoing analysis following the Event!

And don’t forget, Macworld Expo San Francisco begins in just two weeks, so we’ll be keeping up the momentum with lots of dirt yet to be dished….this is a very exciting time to be an Apple fan, and we can say with great confidence that it’s only going to get better from here.