On the subject of strongholds, I should have some free time tomorrow night to finally sit down and go through the books for ideas for Torahime's chunk of the castle.  Thus far, the only thing I've really come up with is adding in an Astral Projection Room that also doubles as a meditation room of some sort, and maybe also working in some sort of wondrous item that provides castings of Cloak of Khyber.  Though, I suppose I wouldn't actually be able to bring the Khyber dragonshard focus for the spell out of the castle itself, so it would be of rather limited use until we could find more 50 gp Khyber dragonshards.