As requested from another thread: I built this up about a year ago based on a great idea posted here.
The parts list & tools are listed in the DIY Blog article. I was able to get all the parts from the list for about $35-40. The only parts I had to buy were the PA/speaker tripod ($25), the 3/4" pony (pipe) clamp ($6), and the black & galvanized pipe pieces (forgot how much, but <$10).
The glitch I encountered was from not being able to measure the diameter on the tripod's extension tube before purchasing (on line). Sure enough, it was too narrow to fit the vertical 1" pipe piece from the t-fitting. And when I took out the extension tube, the main tripod tube was too wide. So I bought a 3-ft piece of 1" pipe and a length of 3" (I believe) single-wall shrink tubing. I heated the shrink tubing over the unthreaded length of the 1" pipe and it brought the outside diameter to perfectly fit into the main tripod tube.
So adding in the unanticipated parts, this cost me about $50. Certainly could have been cheaper if I knew someone with scrap pipe or clamps and looked for a speaker stand on Craigslist. Probably could have been $25 or less.
The pipe slides up a lot higher than the picture shows. Since the tripod uses both a pin and locking collar to secure the extension tube, I drilled holes in the 3-ft vertical pipe every 6" to accommodate the pin. You can see the pin going through the collar near the top of my rear wheel, there's a small cable lanyard attached to it. Also, the clamp rotates 360 degrees in the horizontal axis like shown in the DIY Blog article. And it breaks down to be just as compact, so I can set it off in a corner when I'm not wrenching.
The only drawback is it's a little tippy. The legs don't extend out as far as the model in the DIY Blog article. I'll take a look at how to remedy that, but for now I just position the bike over one of the 3 legs. Also, the seatpost QR collar is just slightly too big to really secure the 3/4" pipe rotation inside the 1" tailpiece, so I just put in a shim.