The fact of the matter is that Star Wars is NOT ending soon. We still have 4 more years and wh knows after that. And besides what would a Halo line consist of? A buttload of cash size scarab, a tank, and some cars? We get that from city and the tank and scarab is too violent for LEGO.
Simply, no. It will never happen due to the fact that it is too violent. We already have weapons from Brickarms and helmet and armor molds from Brick Forge. What more do you want?
EDIT:
Why not make your own?
I have blurred the bad parts of my two Harley Quinn hentai posters and went and blurred the whole "real life" girl poster. For the safety of the little ones.
Sorry guys. I forgot to say that when I am playing with the Gunship it usually ends up that one of the Jedi go in the tank so when this happens I take the clone gear out and put it in the empty pilot seat. :-)