Blizzard's Newest Project?

Diii.net follows up that Blizzard is working on an un-named fifth project based on recent job listings (thanks Eurogamer), though they could also be for one of the projects we know are underway. This new game will proportedly use an entirely new engine (graphic/game? both?) for the final product. Sounds pretty far off to me. Wonder if it's WoW 2? Blizzard is currently working on a World of Warcraft expansion, StarCraft II, Diablo III, and an un-named MMOG that isn't WoW related. thanks bluesnews.com for the excerpt/linkage