It has been confirmed by retailer GAME that GAMEfest 2012 has been cancelled.
In a tweet the retailer stated: "I'm afraid GAMEfest won't be happening this year - but we do have some cool things in the works! Stay tuned."
Though they did hint at a return the following year, when they later said: "By the way - this doesn't mean it won't happen next year. *wink*"