Does anyone know if it can be used for storage? Specifically harkons room. Atfer defeating harkon garan or whatever the dark elfs name is says that "now that the castle is your's, would you like me to restore the hall to the garden". Does this mean we can store items safely? With the abundance of npc's i am a littlle hesitant

I believe all containers are safe, and if you drop any thing it won't disappear. However, display cases do respawn but it'll just respawn ontop of your item, same goes for weapon racks, but only in spots where weapons are already located.

If you're really worried I know the chest in the chapel is safe after you kill harkon.

i hope you are right... all the wandering npcs scare me lolz. i dont want them taking anything or making a container refresh

and if items in the display case or armor/weapon rack respawn doesnt that mean that the cell is refreshed and items would be lost?

No, they just spawned on top of my items.

i found a chest under a desk in harkons room that i will try with some junk and after awhile if it works ill add to it