Its a few years away from seeing a release in Japan, so I'm not surprised SE isn't making a showing, though they could have shown the trailer from TGS2010. You'll have to wait til TGS2011 for info on Versus XIII. They could have pulled the resources and manpower from XIII to help speed it along but opted for a sequel no one asked for.

Ouch!: I don't follow Halo or Bungie, so I didn't know the team has moved on. Its still a funny joke though