Magnetraction is overrated in my opinion. In fact I think it's too much and not the best for someone honing their skills.
Look at the Arbor Coda 157 (griptech makes up for nonwide), Signal Omni 156 Wide, Ride Berzerker 155 but you'll have to check your stance width and angles with your bindings of choice ON the board to see if you clear it, Flow Drifter 156 (do the same thing as with the Berzerker), Salomon Grip 158w (this one will ride a bit shorter with the shape and rocker profile and all), I quite enjoyed this years Forum Destroyer Doubledog for an all mountain twin so if they didn't change it for '13 get a 156w, Nitro Team Gullwing Wide 157, Nitro Pro Series Eero (will fit 12's)...
I can give more details about each one if requested.
Go ahead, drink that kool-aid.
FS: Forum Sauce 142 $200 plus shipping
FS: Flux SE30 $75 plus shipping