First, try finding copper busbar. Second, try affording it.... goodgawd...
Third, ever wonder what the current-carrying capacity of rigid copper tubing is? It's fairly staggering: My calcs yield, ito of number of an equivalent number of #12 solid wire:1/2 copper, thin wall (red): 10 wires. 1/2 copper, thk (blue): 15 wires 3/4 copper, thin: 22 wires 3/32 x 3/4 busbar: 15 wires
Figger 30+ amps per wire (uninsulated, and proly a conservative number), and wow.... 300 to 660+ amps!
Squeeze/hammer the tubing flat, (soft copper tubing no doubt is easier), and voila, poor man's busbar. I used a vise to start, finished w/ a lump hammer. Wished I had an arbor press!
Proly not tap-able like real busbar, but not really an issue w/ nutted-on lugs--HD carries them. HD also started carrying 3 ph panels--fairly recently, I believe--$95-120, about 24 circuits.. Proly one of HD few worthwhile functions is sockin' it to these rip-off electrical supply houses
Altho busbar is not easily available locally, "neutral bars" are--drilled, tapped, ready to go. BUT, in aluminum. :( Interestingly, these neutral bars look anodized--mebbe they're just tumbled nicely--but anodized alum is a much shitty-er conductor than even aluminum. The initial oxidized layer forms within minutes on freshly cut alumn, so if doing radio/antenna work w/ joined alum components, it can be important to make the mechanical joints quickly. fwiw.
-- Mr. P.V.'d formerly Droll Troll