I've seen it done by a guy over at Max-Suz that runs a 1G with a sidehack. (I haven't been over there in a few years, so I don't recall his screen name.) The 2G rear fairing mounts to brackets that attach to the frame instead of directly to the frame, so if you can fab up something there, that's probably how it's done. Since the tank & frame lines are different between the 1G & 2G, the 2G fairing on a 1G doesn't blend together as well as it does on the parent. Also, be prepared to modify the 2G headlights (there are the threads here) to have as good a night vision as the 1G has.