Borderlands developer Gearbox Software was originally considered to create Halo 4. In this month’s episode of IGN Unfiltered, Ryan McCaffrey sat down with Bonnie Ross, head of 343 Industries, and discussed the history (and alternate histories) of the development of Halo 4, among many other topics.
After Halo’s original development studio, Bungie, split with Microsoft, there was a discussion at Xbox about what to do with the Halo franchise. While the ending of Halo 3 was ambiguous enough to serve as a finale for the series, Halo also took place in an incredibly well-realized universe, one which was rich enough to serve as the setting for many more games, should Microsoft find the right studio to make them.
Source: IGN.com Borderlands Developer Was Considered for Halo 4