We bought a rather large, cumbersome trundle bed for the kids, specifically so that they could each have their own space. However, most nights we still find them cuddled up next to each other, sharing one of the beds.
We have been looking at a couple of houses lately, and they already protest when we point out that there will be more space in a new house with one room for the boys and one for Makelle. Corbin always says, "Fine if we can't share a room then, we will just sneak Makelle into our room everynight!"