Curious why no one is looking outside of 80/20 to a more cost effective option? Coming from the solar industry where spans of 14' are common for aluminum extruded rails, there are 100's of options. Of course the cost is about 1/4, if not less, than 80/20 as it is a very competitive market.
My thoughts would be to buy simple aluminum rails of whatever size deemed necessary for the load, buy a welder capable of welding aluminum, and save money. I bought my TIG used for a reasonable sum, and although I am not the greatest TIG welder, I can make two pieces of metal stick together. A MIG with a spool gun is very easy to learn to weld aluminum with, and how a lot production welding is done. Aluminum does take a pretty powerful welder and more importantly a 200 amp main breaker, as they require a 100 amp breaker for themselves (Often a challenge on older houses as they only had 100 amp mains).
Cutting aluminum is super simple. Heck you can use most any power saw or even a hand saw. Just get the right blade. I have a 10" portable table saw that I put a 7 1/4" metal blade onto for ripping fairly thick aluminum. I haven't had a need yet, but could easily change out the saw blade on my 12" compound miter saw to a non ferrous metal blade aka aluminum blade (I have a 14" metal cold cut saw and a horizontal band saw for metal).
Doing a build like most in this thread have done, or plan to do, requires a fairly extensive set of tools both hand and wood/metal working with some specialty stuff thrown in IE: Rivenut tool. I look at it if you can break even and come out owning the tool doing it yourself then take the DIY approach. My hat will always be tipped to anyone doing DIY stuff
Not dissing those that used 80/20 as it has tons of benefits, and looks beautiful. It is the cost that kills me. I have learned a lot reading these threads and will continue to be schooled
until someday I can take on my own project...