Indeed, the "Weeping Willow" is the last obtainable item you may retrieve in the personal space.
Weird, I was just searching for this thread acouple hours ago. I wanted to find out if the tree was the last item or not.
I agree, that was something I was concerned about as well, is that guests can't partake in the game and receive rewards also. Perhaps they'll update it like they do with a quantity of there other personal spaces for the holidays, we'll see.
I have the space, it is fun, I hope it gets an update around halloween with guests gifts too, that is the only bad thing about it, no real guest gifts