Closest is the Fatman. Unlike in F:3/ NV, it has a 2 handed grip with the front being a vertical foregrip. Thing is, if someone adapted the animation, they'd have to scale the Thompson down so it could be held shouldered, instead of at the hip, as well as adapting the hold to fit actual firing and reloading. Then I guess you'd have the vertical foregrip, but instead of hipfire, it would be aimed with a vertical foregrip.