In reply to HenryCowan:
I have thought about doing this as well. (however the girlfriend says no)
What i was thinking is building a frame (wooden) within the the room, basically a cage.
then build your wall within this as normal, but attaching to the frame rather than room.
depending on the size it should be more than stable enough, however weight could be added to it, to stop any movement... sand bags in or on the base should do the trick.
depending on how funky you'd like to be, you could also build in a wall with changeable angle.. I'd do this with metal plates and steel cross bars, but you could achieve something similar using wood.however this could have to much play in it.