http://www.guitarcenter.com/Yamaha-SLG110S-Steel-String-Silent-Guitar-H71294-i1788063.gc
These are very interesting, very packable and have the advantage of not bothering anyone. I must say, as a semi-professional with lots of studio and professional performance under my belt, I don't think I bothered anyone. I always had people ask me to play more and let them hang around rather than the opposite. Met some great people through it. I've also been on the other side, enduring endless 2 chord jams with a backpack Martin and a recorder or pennywhistle. I didn't know whether to shoot them or myself. I usually pack up and move on.