Microsoft CEO Steve Ballmer might be trying to steal a page--not to mention a little thunder--from Apple CEO Steve Jobs tonight during his Jan. 6 keynote address at the Consumer Electronics Show here in Las Vegas.

Rumors are circulating that Ballmer will reveal a tablet PC built by Hewlett-Packard, courtesy of New York Times blogger Ashlee Vance, who paraphrases unnamed sources as saying, "Mr. Ballmer will show the as-yet-unnamed HP device, which will be touted as a multimedia whiz with e-reader and multitouch functions."

This rumor comes a few weeks before Apple is rumored to be debuting its own tablet PC in San Francisco. If the Microsoft scuttlebutt proves true, I'm betting the device will be the much-rumored Courier tablet. Back in November, Gizmodo took supposedly leaked information about the Courier and ran with it, detailing a device that allows users to surf the Web, draw and write in a digital notebook, and clip, "tuck" (slot away for later use) and paste images.

The irony, of course, is that after so many months of attention being focused on Apple's rumored tablet PC, Microsoft risks being seen as a follower even if it announces its own device weeks in advance. Granted, Microsoft has been working in the tablet space for awhile, but whatever device Ballmer debuts--if Ballmer debuts one--will need to be a radically different animal than Microsoft Surface and other past tablet initiatives.

If Microsoft's tablet PC is truly innovative, and if Apple does indeed announce a tablet PC of its own later in January, then the stage is set for a very interesting battle between the two companies in the latter part of 2010--the results of which could potentially inform the evolution of PC hardware for some time to come.

HP, meanwhile, has announced a variety of laptops, desktops and notebooks here at CES (our very own eWEEK CES slide show can be found here) but has made precious little mention recently of tablet PCs or e-readers despite being such a huge manufacturer. Of course, HP could be saving such an announcement for tonight, when it's all but assured a massive amount of publicity thanks to the opening of the show.

I'll be live-blogging Ballmer's speech, so check here to find out if he takes the stage wearing a black turtleneck and sneakers.