Bungie actually worked on Halo Chronicles for about a yearthey were close to getting to production when it was scrapped. I imagine it was the confluence of Bungie's independence and Jackson's lack of involvement that killed the project.Weta Workshop was working on pre-production for the Halo film, and I think Peter himself was writing for a Halo game side project but that was being developed by some other team. Both those projects were cancelled.
I don't think Wingnut Games ever received funding for anything. The idea was they would produce original IP that I think Microsoft would fund. But when everything else fell apart and Peter continued to be busy with films, nothing ever got off the ground.