Most of the shared nurseries we've seen involve cribs, side by side, like the room shown here. And even as babies, a little delineation and demarcation of your space versus mine is a good idea.
To achieve the look and feel of separateness without actually dividing the space is a great idea, especially in a small room. Here, an old wood door painted bright orange visually bisects the sleeping area in the room - yours and mine. We think the painted door is genius - it's more substantial than hung artwork or a mural on the wall, but not obstructive like an actual room divider.
(We're betting this mom will secure the door to the wall as the babies get older, if she hasn't already.)
See more of this home: Stephmodo