This skirt/pant thing is part of a set based on this real life modern ao dai which can be bought from aodaiminhthu.com, made at the request of PocketPet.

Be Sure to check out the shirt too!
http://admin.imvu.com/catalog/product_info.php/products_id/263566

This is what the set currently looks like, but I'm hoping to redo it in the all in one form of the purple dress.