Round here people dump worn / torn leather sofas on the street. I've skinned a couple for odds and ends of leather, out in the dead of night with a Stanley knife. I seem to remember you are doing this on a tight budget - might be fun to obtain your covering material that way, especially if you can find something outrageous in gold, or leopard-print, or (depressingly common in abandoned furnishings around here) white!
I once played a gig in a Sally Army hall where the house PA involved column arrays covered in heavily (think ski jacket) quilted metal-flake vinyl. Like, cosmic, man
(and speaker cloth - how about some retro curtains when the charity shops re-open? I have my Nan's (died about 1980) tucked away somewhere for just such a purpose...)