With its outside walls clad entirely in wooden louver boards, a four-story building that opened last week in Tokyo's quiet Tomigaya residential district could easily be mistaken for a chic new gallery or boutique.

Chic it is, but rather than being an arty space, it's another example of a trend -- that is, harnessing the arts of design to the living-space demands of those no longer content to live in a few small, cubic rooms.

Called Luceria, the complex is one of a growing number of "designer mansions" currently beloved of trendy lifestyle magazines and stylish young people -- typically singles and couples in their 20s and 30s with no children -- who disdain blocks of identical apartments.