FlavourArt makes a gin flavoring, and someone, Flavor West I believe, sells a martini flavoring. But I don't know if anyone sells a gin flavored
ejuice. I haven't yet tried either flavoring, though have heard good things about the FA one.
It has crossed my mind to try to mix a
juice with the herbal notes from the gin, so I'll be interested in what others have to say in your thread.