I've seen a lot of single tier and two tier systems on this thread, but there weren't too many three tier systems. I have been working on this for a while, but finally finished it, and used it for a brew this week.
I built mine with the idea that it should be able to store in a 24"x24" floor space in my shed. I wanted the system to be portable (if I wanted to take it somewhere) and be able to brew anywhere with or without power.
The main tower is 24"x24" and about 5' high. It has two BG12 burners, one for the HLT and one for the boil kettle. The bottom shelf is set at about 22" high, so I can syphon directly into the fermenter.
The shelf on the right hand side is built using two heavy-duty folding shelf brackets, and holds my Gatorade mash-tun. Its set about 45" off the ground (just enough to syphon into the BK). Because it folds it means that I can fold it down and store the whole system easily, without taking up extra floor space.
The top is 60" high, and holds the HLT, with another BG12.
I attached the burners is attached using threaded rod and a standard piece of angle-iron, so I can adjust the height. The threaded rod has a nut on it at the top (to make it hold through the fitting), and two at the bottom to sandwich the piece of angle iron.
I was a little afraid of condensation on the top bracket dripping back into the BK, but that seems to be ok (theres enough distance to not make that an issue).
The biggest problem I have is with the zinc on the crossbars flaking off - but that will go away soon I hope.
Since I wanted to be able to move this, I put harbor freight 7" or 8" wheels on the back strut supports. The supports are about an inch off the ground, and you can see where I had to level the stand to get it sturdy on my uneven (muddy) ground, but it held up well, and was nice and sturdy yesterday.
As you can see I still have to figure out a good way to attach the propane manifold, but the zip-ties are working for now
I'm really glad I did this.. I realized that I spent way too much time lifting and balancing pots and fermenters before. Now brewing seems so much easier