I really don't see Microsoft handing such a valued franchise to a third party developer. A port is one thing but to hand the developement of the franchise over to GearBox seems highly unlikely. It could be that GearBox is working with Microsoft on bringing Halo3 to PC or maybe Halo:ODST or Halo:Reach these projects would also be no talk subjects.
In short GearBox may have been asked by Microsoft not to talk about Halo. Not to mention many studio's set strict guidlines as to what they are willing to talk about and what they are not. Touching such a hot subject as Halo4 would be foolish, that doesn't nescessarily mean they are making Halo4.
Also who says Halo4 will come to 360? Chances are Microsoft has another console in the works for 2011 just like Nintendo. So with Reach coming fall 2010 theirs a good chance Halo4 will be a launch title for Microsoft's next console!
-JC7
"In God We Trust - In Games We Play " - Joel Reimer
