There are issues, I think, regarding 'dynamic' objects such as placing your own tables, etc. in an already established map. I don't think it is really possible, which is why such a thing has never been really realized, due mostly to engine limitations. Thats just what I remember from memory and the type of answers I've picked up on the (many!) threads regarding this sort of thing.
-The only real answer to this being to have a variety of Housing maps, which as you could see lately with the advent and release of SDK, players are helping considerably with.
If you really want variety, sad to say, its probably most helpful if you helped generate interesting (and practical) housing maps for people to peruse. In this way, hopefully, choice pieces might be worked into game.