I tried searching for "living ghost structure" and having perused the answers, there's nothing close enough so here goes...
If you enchant a building to make it mobile, and then when you are prepared to die and cast Haunt of the Living Ghost on yourself, would you still be able to move your tower around and use it as your haunt? I'm considering enchanting a tower as a Talisman (so while I'm in contact with it, it shares my Parma Magica - avoids losing it to the first PeTe spell that comes flying) and then having it move around Howl's Moving Castle-style. I'm considering using this with Haunt of the Living Ghost so I can continue to make mischief long after death.
I've pondered a couple of others - you could use Ring, but anything short of a diamond cable used to make the ring will probably get broken, and it only requires one break to end your existence. Boundary plus a few magnitudes is cool, but gets very expensive. I've worked out that boundary plus 8 magnitudes (for a level 90 effect) covers a Tribunal, as it's just larger in land area that modern Spain + portugal (all of Iberia) or modern France (Normandy + Provence). and considerably more than Ireland, Italy or mainland Britain. Maddeningly, Ireland is slightly above the size of boundary + 7 magnitudes...