Respectfully, since I also wish this could be the case, I have to disagree.

The problem with this, is that you are thinking of instances as free land. From an IT perspective (I work in the field) instances mean an entire different server allocation. literally, each player with an instanced house, means millions of server allocations. now this is okay with inns, due to them not having anything special in them, but once you have to start saving configurations, the number bloats exponentially.

Honestly, it would be easier from a server resources perspective to add 100 wards per server, than to create instanced housing. its more efficient, and you gain network bandwidth by not transferring between file servers to enter your house.

My opinion, though.