The guy who revealed the first screenshots of a game on the Revolution (taken from a scanned magazine) also has some rumors about a FPS MMO based on Halo that is still on the planning stage. The scan is almost unreadable, but I have super powers:

Bungie’s other project

Last issue we told you about Bungie’s Forerunner Halo project, and now we’re gonna let you in on another game the developer has cooking – a project currently codenamed Orion. Bungie is teaming with Ensemble Studios for this Halo-themed FPS MMO on the 360, and the game is currently still in the planning phase. So details regardin Orion – like Forerunner – could change.

Another April’s fool?

My guess is that this is going to be a version of Halo focused on the multiplayer, but I doubt it will be a true MMO. The term has been rather inflated lately.