We need storage rooms! Most of my house space is dedicated to walls full of SDBs to store items I rarely use. Not only does this cause considerable lag, but it prevents me from decorating as I'd like because I need the space for SDBs. It would be great to be able to place a door in any wall that leads to a small storage room which loads separately from the rest of your house or tower. Then I could cram all my storage SDBs into specific rooms.
I'd suggest making these storage rooms purchasable only with credits. They aren't essential to the game, but desirable enough that I'd pay money for a few of them.
If you allow storage rooms to be placed Inception style, a storage room in a storage room, then maybe chaining like 10 of them could be considered a tunnel and allow the player to choose where in the world it exits. Or they could be chained together to create labyrinths with small themed rooms.
Then we can bust open the storage rooms of inactive players and have storage wars! Well, maybe not that one...