I really think we will see something from SEGA in the very near future, and the reason why I think so, is because there is a definite need for something better than the current offerings from Sony and Microsoft to fill up the market. The stagnation that has been ravaging the videogame market for years, is simply because Sony and Microsoft don´t have any idea what they are into, don´t know games (like Hiroshi Yamauchi said of Microsoft), and there pump out a mediocre bunch of games, which if it wasn´t for the few highlights such as Halo and Gran Turismo would have long ago landed the whole industry where it was at the last market crash. Yes, I mean this!
They can deny it all they want, but I know for a fact that SEGA, as one of few, and even though they don´t have a console anylonger, has salvaged a lot for the gamers survival on said two platforms during this stagnation, by producing titles being way above the average and below-average games seen flooding the market. I have to merely look at the reviews scores for console games on, say, IGN, to tell how few games are really any good or really, really good! It´s companies like Nintendo, SEGA, Namco, Konami, Square-Enix, Rare (I almost didn´t want to mention them, but did anyway, as I still believe they have potential to return to the glory of the past once again) which continue to keep the market floating, and not sink like a certain luxury liner did in 1912!
So SEGA probably knows they could make mega bucks by returning to the hardware market, but only if they time it incredibly well, and that would mean not until either Sony or Microsoft throws in the towel! Some might argue that will never happen, but I think that one of them will have to bow out for reason of unprofitablity!!!
I don´t think SEGA would have a problem at all attracting support from third-party developers, since they are going to be forced to launch games on several platforms in order to remain profitable, and looking good in investors- and share-holders eyes!
So, perhaps we shall indeed see, that the two companies who were once the two most successfull in the business, with NES/Master System and SNES/Mega Drive, will once more return to the two top spots and duel it out again head-to-head! The emptiness left by the current two market leaders is bound to be whisked away, and filled out by pure gaming love from the Videogame Gods!