At a preview event for "WET," Pete Hines, VP of Marketing and PR for Bethesda, mentioned that an announcement is "coming in the next month or so" regarding another 2010 release for the company. Currently confirmed 2010 games include:
"Fallout: New Vegas"
"Rage" (developed by the Bethesda-owned id Software, published by EA)
Pete was quick to confirm that it's not one of the various iPhone projects that have been bandied about at id or Bethesda, nor is it the game that Todd Howard's development team at Bethesda Game Studios is working on (he said it'll be a while before we hear anything about that).
So what could it be? My guess is a remake of the classic "Where's Waldo?" game on the NES, which Bethesda developed in 1991. C'mon, it's due!