EA is the most likely candidate. Imagine what kind of leverage they would hold if they had their own exclusive console and you couldn't get Madden, Live, Tiger, NHL, FIFA, etc. on any other console. You'd have a built-in audience of sports gamers who'd snap it up at the right price.

The Atari 8000. Believe it.

probably EA or SE

Except that the side effect would be that any exclusivity deals EA had worked out with the Major Leagues would disapear (they want games based on the league across all platforms) and they would potentially have new competition from Nintendo, Microsoft, Sony, Activision, Take 2 and several other major publishers ...

The market has never really been able to support more than three consoles.
This has been true for more than a quarter century. Even with the market getting larger, I don't see this changing. So I see no one entering. Who would want to produce the next Atari Jaguar or 3DO or NeoGeo (famed fourth consoles).

Mike from Morgantown

The only company that I could see as a remote possibility would be Apple and I think Apple would make a handheld instead of a console. I also can see totalwar23's point of several computer manufacturers coming together to make a console, but I think that is more of a remote possibility.

Apple,EA and Sega.

apple, EA

Apple already has a console. The iPhone/iPod touch. There will be no other gaming devices from major manufactures, the market is already overcrowded.

If either Sony or MS drop out I could see Sega taking another crack, they have experience are having a pretty decent resurgence and would profit if they could rebuild their first party franchises back up to not being total shiet.