Okay here we go!

So Courier Six was shot in the head, only they actually died, buried in a shallow grave and left to rot. 
Mr. House now needs to hire a new group, finding some of the best mercs, business men, scientists, and scavengers her assembles a team that would be divided up to hunt down Benny and get the chip, negotiate with the satellite factions like the khans, brotherhood and boomers. And the scientists to help get his secuitrons working in the mk.2 state. 
As we progress their could be arguement as to wether we kill house or leave vegas under his rule, maybe even some of us sympthize with the NCR or Legion and we get torn apart, or all decide on one faction and become the ultimate force working to help new vegas (or destroy it.)