I was watching Episode VII the other day and was thinking about the stormtrooper that attacked Finn. He had what looked to be some sort of riot shield and thought, "What would happen if my group ran into a minion group of those type of stormtroopers?"

So are there stats for a shield like that?

The Riot Shield is in the colonist splatbook "Far Horizon" it provides a def boost to the wielder(s).

For what it's worth, the First Order trooper riot shield gets statted out in the equipment section of the TFA Beginner Box's Rules Booklet. It's not as beefy as the version found in Far Horizons, but provides a +1 to both melee and ranged defense.