Quite possible to do..
I won a game on dominion today in <8 min (Was like 7 min 22s), you can even scroll through my recently played to find that game.
All you need to do is cap top, and all still be alive / have alot of hp left.. Hope they are idiots and run @ you 1 by 1 in the lane, as you push their middle turret.
As long as your bottom lane manages to kill bottom lane, and push the other teams turret, once you capture all 5 points, its almost instant loose, as the 5 health packs allow a good sustain for at least 2 players to defend the points why players go get health, and by this time, your team has +1000~+1500 more gold each than the other team, and your items alone win you the game.
Once you secure them 5 positions near the start of the game, its a sure win..