It's the client's so I don't know where they got it from but the Oliver bed from Feather and Black is a similar style and comes in a variety of sizes. A pair of them in kids bedrooms looks very sweet.

http://www.featherandblack.com/beds/metal-beds/oliver-bed

http://www.featherandblack.com/childrens/beds/iron-beds/oliver-children's-bed