When it comes to a safe/chest with a heavy cast body, heavy cast door, and a full sized lock it is unlikely to find one much smaller. In order to fit a full sized lock inside the door dictates door size which dictates body size. Post a picture of your door and lock. Curious to see what style it is.
The one I reworked was about 12″ in all directions and did have a hole in the back side for securing it. I was told it was a wall safe but it was suggested that it could have been an inner chest.
