We’re just 48 hours away from getting our first look at the long-awaited, next-generation iPad—or that’s what we’re expecting, at least.

Indeed, with all the leaks, rumors, and wild guesses we’ve been hearing in the past months about the next iPad, it’s easy to forget that Apple hasn’t even officially announced the thing yet, much less doled out any details or pictures.

Since we still have a couple days to kill before Apple ends the suspense, now might a good time to summarize what we know, what we think we know, and—most importantly—what we definitely don’t know about the iPad 2.

What we know

The original iPad is still the only iPad, for now: Like I just said, Apple has yet to announce, acknowledge, make veiled references to, or even hint at a new iPad. Well … strike that: during Apple’s most recent quarterly earnings call, Apple COO Tim Cook told analysts (who’d been asking about competition from impending Android-based tablets) that “we’re not sitting still” in terms of the tablet market, a remark that may qualify as a vague hint.

Apple is holding an iPad-related event Wednesday: The invitations went out last week, with an image showing a Mac OS calendar page peeled back to reveal an iPad peeking out from behind. The caption: “Come see what 2011 will be the year of.” So yes—the writing’s on the wall, but the invite stops short of saying “come meet the iPad 2″ or anything like that.

Last but not least, we know that … uh … : If we’re only talking about things we definitely know about the next iPad … well, strictly speaking, we don’t know much more than what I just outlined above. Oh, wait: Wednesday’s Apple event will be held in San Francisco, at 10 in the morning local time. And iPad-related topics are on the agenda. There you go.

What we don’t know

What it’ll be called: Everyone’s been calling the next iPad the “iPad 2,” and there’s even a new (and likely fan-generated) rendering of the next-generation tablet floating around with the “iPad 2″ name stamped on the back. But as far as I know, no one’s come out and reported that the iPad 2 will, in fact, be called the iPad 2. Apple’s been known to throw curve balls when it comes to naming its next-gen products (like, for example, the iPhone 3G and 3GS), so I wouldn’t put all my eggs in the “iPad 2″ basket.

How much internal storage it’ll have: Will we get an iPad 2 model with 128GB of built-in flash storage, or will the largest next-gen iPad still top out at 64GB? Hard to say. There have been scattered reports of iPad 2 mockups with “128GB” etched onto the back, but that may be more a case of wishful thinking than a concrete clue. I predict the priciest iPad will still offer “just” 64GB of flash storage (which still costs a premium compared to conventional disc-based hard drives), but that’s only a guess on my part.

How much it will cost: Apple is in the habit of marking its next-generation products with the same price as the previous generation, and there’s no reason to believe that Cupertino will change course with the iPad 2. Again, though, we’ve yet to hear any reliable rumors about pricing. (For the record, the current iPad costs anywhere from $499 for the 16GB Wi-Fi-only version to $829 for the 64GB 3G iPad.)

When it will ship: Conventional wisdom initially had it that the new iPad would probably hit stores about a month or so after being announced, but now there’s talk the iPad 2 might be available immediately. Maybe so, but personally, I’m hedging my bets until Apple serves up the official line.

What we think we know

Slimmer profile, less heft: Just about everyone seems to agree that the redesigned iPad will be “smaller” and “lighter” than its predecessor, complete with a flatter back and tapered edges. Indeed, chatter about a slimmed-down iPad 2 shell has been so consistent (not to mention a logical progression for the iPad line) that I’d be shocked if it didn’t come to pass Wednesday.

A camera, or two: Another consistent iPad 2 rumor has it that Apple will fix one of the biggest criticisms of the original iPad—namely, the lack of a camera. A recent Wall Street Journal story claimed that the new iPad will have “at least” one camera in front for FaceTime video chat, and there have been countless sightings of purported iPad 2 cases with strategically placed holes in back for a second, rear-facing lens. While there still seems to be some lingering doubt about a second camera, a front-facing lens is pretty much a no-brainer, particularly since each and every iPad competitor out there has one.

Same-resolution display: The hot rumor back in December had it that the iPad 2 would arrive with a sharper, 2,048-by-1,536 pixel display, good for a “retina”-style screen similar to the one on the iPhone 4. But the latest word and some leaked spy shots have poured cold water on the buzz, and it’s now looking almost certain that the revamped iPad display will come with a 1,024-by-768-resolution display, same as the original. Oh well. (Don’t worry; recent chatter has it that the iPad 3—yes, 3—might get the retina-display treatment.)

Faster, beefier processor: “Dual-core” is the gotta-have spec when it comes to this year’s hottest smartphones and gadgets, and the iPad 2 is no exception. Most believe the revamped tablet will get an updated, dual-core version of Apple’s A4 “system-on-a-chip,” complete with 512MB of RAM (double the 256MB RAM in the original iPad) and some seriously souped-up graphics capabilities.

Better speaker: The new iPad is reportedly in line for an improved, “wide-ranged” speaker, with the more prominent speaker grille said to be sitting right where the current three-hole speaker on the first iPad lives. Or so they say.

No SD card: An SD (or microSD) card slot on the next iPad would allow for easy memory expansion and speedy photo uploading. It’s a nice idea, but early buzz on Apple adding an SD card slot to the iPad has given way to near-universal agreement that it won’t actually happen. Bummer.

No 4G support: Not on Verizon Wireless, at least, according to the Wall Street Journal, which adds that the 3G version of the iPad 2 will be available through AT&T and Verizon but not Sprint or T-Mobile.

Source: yahoonews, W3