Rather than built in closets, the European tradition is to have armoires to store your stuff in. The armoire pictured below is my favourite one of the ones that my dad built. Though its actually in the living room at the cottage, rather than in a bedroom. Its such a nice compromise between elegant and fancy, with very clean lines.

Here's another one, in one of the bedrooms. What's interesting about this one is the paneled doors done with curves and angles.
More of my dad's Original furniture