Hi - as a first time hammocker and poster to this thread - thanks to all who have contributed to this great idea. Reading through the thread was a quicker, less painful, and much cheaper way of prototyping!
Re building a rig - I have some bits at home that might work well - I've 6 light steel tent poles and the tubes from a trampoline legs that slot together. I'm making a small joining piece at the top of each tripod that the tent poles will slot into and the connection for the ridge pipe will run through. I'm also making a folding rigid star shape leg spreader to make setting the legs easier. Finally the trampoline legs jointed together have a nice upturn at each end (where they were designed to support the trampoline frame) which give an extra foot height to the tripod height. Should pack down well and be an easy set up - will send video of outcome - could be wildly amusing!