Gearbox creating Halo 4?
Rumour mongering
Rumour of epic scale this morning as we hear rumblings that Gearbox (Brothers in Arms: Hell's Highway) could be the studio behind Halo 4, Joystiq suggesting that the title might be created for release alongside the next Xbox hardware (whenever that might be).
The North American Official Xbox Magazine apparently spawns this rumour, which in a way adds weight, while Gearbox boss Randy Pitchford has in the past hinted at a very big new title.
"It’s, like, look-at-our-line-up-and-imagine-something-even-bigger kind of big," Pitchford teased, speaking in early 2008. "I’m directing it myself. I can’t mention it publicly yet. When you find out what this is, you’ll likely agree that I can’t oversell this one."
At the time, rumour suggested that game might be set in the Halo universe, while Bungie have also implied that they're not working on a traditional sequel to Halo 3 - rumours abound that their next project was either a new IP, or a squad-based Halo shooter.
More on this as we get it.

Comments
As long as this doesn't affect development of Gearbox's other game Borderlands, more power to them.