After finding this thread which gave me the perfect solution for my lack of trees in my backyard I went out and bought all the wood and bits I needed to whip up my 'mk1' tripods.
I then had an issue finding the tubing to run between the tripods... I couldn't find anything like what I have seen in the photos here.
After some online research I found a guy who specialised in aluminium tubing, so i went to his workshop and this is where the concept for the 'mk2' tripods was born!
I have ended up building telescopic aluminium tripods that stand approx. 2 metres tall (1.2 metres when compact) and an aluminium centre beam (scaffolding) that is strong enough to hang body weight from the centre. The reasoning behind going this thick was to avoid the beam from bowing and so if someone pulled themselves out of the hammock using the beam it wouldn't collapse above them.
I have slept in my WBBB hanging from the mk2 and it is perfect and strong. I have also made the centre beam almost 4 metres long so I can hang my WB Mamajamba tarp from it too.