Making Objects Ethereal

[TheBarbecueChip]

Help me Internet! I remember reading somewhere (I think it was in a 3.5 book) about a spell or item that could turn entire mountains ethereal so that a powerful character could build on the site where the mountain was and be safe from spells or effects that would allow his/her enemies to pass through the ethereal plane and pop up unannounced in their fortress. I want to use this situation in my campaign but I can't find the book. And yes I know things like walls of force can produce similar effects but I really like the style of having an ethereal mountain occupying the same place as your material fortress.

[With a box]

Plane shift with it to ethereal plane

[TheBarbecueChip]

Plane Shift only works on creatures.

[Forrestfire]

Psionic sandwich into the mountain and then plane shift that to the Ethereal Plane. Then unsandwich it. Or animate objects it. Objects, unlike dragons, only go up to Colossal, so you only need CL 32. A greater consumptive field should get you there.

[With a box]

Then use PAO
PAO mountain into living human
Make him sleep/knockout
Plane shift to ethereal plane with it
Unconscious considered willing
Dispell PAO