Cheese... He's asking about the stand structure itself. That erector set looking stuff is called Unistrut. It's main usage is supporting pipes and conduit in industrial settings. They have all kinds of shapes like angles, U, and boxed sections. Then they sell all kind of connectors like angles, crosses, tees, etc along with the bolts to hold it all together. It's inevitable that anyone that makes hobby type things with Unistrut, you'll find that they work in some industry that uses it a lot and some of it walks off the job. No one in their right mind would buy it at retail price for this kind of project.
And you're right.. hard plumbing is crazy and expensive. I'd at least have a short section of hi temp hose as a stress relief connecting each vessel to the bird's nest manifold. You need a frickin degree in boolean logic to set all the valves per function.
