It's too late. Just Google "extract nicotine ecigarettes" and you will see the horse is already out of the barn. There are too many eCigs floating around out there that can be refilled indefinitely, whether or not the FDA bans further sales.
In case anyone hasn't read it, here's the ASH petition pushing the FDA to ban eCigs.
You can almost hear the antis keeling over dead in unison, since they count on the smell of tobacco to warn them that airborne nicotine molecules are present. Even the thought that they might be inhaling nicotine molecules unknowingly could be enough to trigger an acute attack of paranoid anxiety, possibly triggering a heart attack or stroke.