RE: carbon fiber rods (where to order)
Do a search for DIY kite builders. They sell CF and Glass tubes, solid core rods, and other shapes that all telescope together. In other words buy the next size as well to make end joints easy and reliable.
I bought the stuff from a certain place on the internet a while back that I forgot about to make a VERY light weight carbon fiber tripod for photography. Likewise I also bought said rods for a frame in a backpack.
Sorry, I have forgotten their online name. I found them through backpackinglight.com. I found them to be the cheapest and best solution. Go to site, ask under the forum of Build Your Own Gear and ask for the site. You will get a quick response.
PS. Kite sites also sell tape that will VERY easily repair mylar/nylon covering. Comes in colors and different widths. Sticks like gangbusters and is amazing stuff.