I am almost positive it is still ILLEGAL. When you put a front pistol grip on a handgun you are manufacturing a short barreled rifle which is illegal. ATF defines a handgun as a firearm that only needs one hand to operate when you put a vertical foregrip on it you are making a gun that uses both hand to fire
Here is ATF's ruling on it
http://www.atf.treas.gov/firearms/041006-vert_grip.htm