In the past few days, Margot has made the big transition to sleeping in a 'big girl bed.'
It's been a pretty smooth transition. Since we moved and her crib was dissembled by the movers, I figured she was big enough and mature enough to sleep without bars. (Plus, I didn't want to reassemble it.) Much like potty training, it's gone by without a hitch. She really makes things so very easy for us but being perfectly amenable to all of our suggestions (ie. "Let's get rid of your crib that you've been sleeping in for the last 2.5 years" or "Let's go to London for the summer and induce jet lag" or "Let's move you to a new apartment where your new room is 3/4 of the size of your old room, which was already tiny!").
Since her room is so small, there really isn't any room for a twin bed, so she's just sleeping on her crib mattress on the floor. It'll do until next June, when we will probably move again.
The only issue with Margot's transition to a bed is that Portia thinks it's a new place for her to sleep. The other night, Margot cried out for Brodie, and when he went in to see what was the matter, Portia was sleeping on the pillow and Margot was at the bottom of the bed. Since then, it's been the story of Goldilocks and the Three Bears: whenever we come home, Margot's bed is all messed up because Portia snuggles down under the covers while we're out.
Anyway, they are working it out, slowly.