Last night we received an invite from Facebook to a “mobile” event at its HQ next Wednesday. There are no clues on the invite about what the event could be about, so we’ve brainstormed a bit and have come up with four possibilities, with #1 being the most likely and #4 the least.

image001 4 things Facebook might announce at its mobile event next week

Of course, Facebook usually announces a couple of different things at the same time, so perhaps we’ll see a couple of these below (or something completely different). We fully expect to hear a lot of mobile-focused statistics, but those won’t be the focus of the event for sure. So without further ado, here’s our best guesses as to what we’ll see on November 3 in Palo Alto:

1. New mobile apps, including a an iPad app

It’s been awhile since Facebook did a rethinking of its mobile apps, and it would seem about time for the world’s largest social network to redo its suite of mobile apps, possibly with Skype and Facebook Credits (for mobile payments) integration. Many people are especially hoping to see a redone Android app, as of all the platforms, the Android app is probably the most lacking. Along with a refresh of apps, nearly everyone here at TNW is hoping that Facebook will roll out an iPad app next week – if they don’t, we’ll certainly try to pry a due date out them.

2. Facebook Places check-in deals

A few days ago, we relayed a report/rumor that Facebook is already running check-in deals for Facebook Places with a select number of partners. Facebook wouldn’t comment on this, but they didn’t deny it either, so it could be that this will at least be a part of the announcement (again, it would be a nice feature in a revamped line of mobile apps).

3. Facebook mobile SDK, app store

In anticipation (or perhaps in conjunction) with #4 below (you probably already know what that is), Facebook could possibly announce a mobile SDK platform for developers to build games and other mobile apps for its own mobile OS or perhaps a Facebookized-Android OS. Announcing the platform a few months before it actually launches its phone (yes, I just gave away #4) is what both Apple and Google did before launching its phones to world. So to no one’s surprise…

4. A Facebook phone

Yes, the widely speculated Facebook phone. The world’s largest social network offering an optimized phone/OS would be somewhat risky at this point, though Facebook has certainly taken risks before (with many of them paying off handsomely). This would be a risk into the hardware sector – with a partner of course – (unless it’s just going to build an OS), however, and as such is a different kind of risk than it has taken before.

The real question in our minds is who would the Facebook phone be for? Would it be a play at developing markets, perhaps leveraging deep Skype integration? Would it focus on mobile payments? Or does Facebook really want to take on the other mobile platforms head-on? Would it just be another “flavor” of Android in conjunction with one of the carriers/phone manufacturers? We might just find out next Wednesday – tune in here and we’ll let you know!