Have you checked with local show breeders in your area? We often times have dogs in the 1- 5 year old range needing the perfect forever home. They are always well mannered and house broken (well almost always lol) because they have been our pets and show dogs. Some dogs just don't like to show or we have held back a puppy to show and it just did not have what it needed to win in the ring in one way or another.
We do have a pretty heavy screening process as we love these guys and want them in forever homes.
Where are you located? If I don't know of anyone in your area, you can check with the Boston Terrier Club Of America's breeder refferal person who can give you names and numbers of breeder/members in your area. There is also a members website page on the BTCA site you can browse.
http://www.bostonterrierclubofamerica.org