While all of these answers thus far give examples of outside showers (and I have the Texport type and it is great) NONE of these answer the OP's question. The one he shows certainly appears to be a kit that attaches to the outside of the trailer and folds up as a unit. Downtheroad's response has probably come closest.
To answer the OP's question - I've never seen onr like the one you posted before. It certainly looks interesting. I hope you someone here on the forum actually has a real answer for you.