We built that one ourselves ... and then rebuilt it and added some braces in after losing the roof :-S ... saved quite a fortune on what it'd cost if we'd bought it.
Although we do have gutters along it's length we don't save the water ( not my choice ), although it takes 4 water butts per watering ( sometimes 3 * daily ) so we'd not save much I guess ... even here in uk where summer is measured in seconds :-S
The rest were either pre-existing or ready built/bought ... all are a tad smaller