Well, this may not be what it is, but there is a good deal of evidence that it could be AMD. First and foremost is the last sentence on Anand's post that he was going out there:
"If it turns out to be extremely impressive I'll do something special with my next post to let you know."
Now, if we're to take that there was something done with the next post, the passing reference to Hammer would be it:
"Product's like AMD's upcoming Hammer. . ."
Also along that line of reasoning is this line:
"With that said I'll be quiet for a few more weeks and then there will be a lot to talk about."
Which corresponds with the post at Van's Hardware here
Van's Hardware Article where there is also a hint towards something being announces in a few more weeks:
"Behind closed doors and under NDA, the chipmaker [AMD] also delivered some of the most interesting and exciting news of WinHEC. AMD will publicly announce details of these confidential disclosures in the coming weeks."
There is also the hint at Tom's Hardware here
Tom's Hardware WinHEC Article that there is something happening at AMD:
"It all bodes well for AMD's continued confidence in Hammer, or is there something else afoot? There's something else afoot. For some peope it's going to be the equivalent of the discovery of the monolith in 2001: A Space Odysee."
The only supposed problem with all this proof is the statement that it's a company that nothing's been heard from in awhile. What's partially interesting about this statement is that it's the same as the post on HardOCP, both say that it's a company we haven't heard much from in awhile. This similarity could, therefore, quite easily be the result of this company's PR department. In a way this could also turn out to be AMD, since despite all the talk about them, the last thing of real interest that they did, not counting the thouroughbred mobile release this past week, was demoing Hammer at IDF, which was close to two months ago. Granted this isn't very long, and other companies haven't been heard from for quite awhile more than that, but if this statement was indeed the creation of a PR department that they asked the site admins attending to put up if they put up anything, then two months would easily be long enough for them to make sure a claim.
Well anyway, that's the most logical conclusion that I've reached as of yet. There's a lot of proof that it's AMD, but that little statement that might be saying it isn't. I wouldn't trust the statement too much, as if the company is indeed AMD, then that nice little statement would be a purrfect red herring, true in a way, but leading away from the truth.