It is possible.
So why not try? Have the buildings in the same locations for every gamer on the map once you pay to open the door, the doorway becomes the portal inside the same as any dungeon or instance.
You purchase the deed to the house, that attunes you to that property. You can have people come visit by group invites.
The Homes if not in-game could be a save/safe state that allows you to play off the HD...maybe? To help keep the servers from overloading.
Guild Mansions/ Faction Houses
You join a guild/faction and then you are attuned. I think it would appeal to more gamers if they did do guild halls, that were modifiable. A place like in the homes in skyrim. Racks to purchase for placing weapons made instead of a bank. Allowing personal trading. Even setting a price of gold to be exchanged for the weapon on the racks...if the player is not on when you are.
~Chupa