I have seen a few nice layouts on Brass chassis, as well. Easier to
work than steel, and you can still solder to it. I built some tube RF
decks on 1/16" brass sheet stock, and mounted them into a steel cabinet
years ago.

I think RL Drake used copper chassis on their tube ham gear. Looked
real nice when new and shiny! I've build some equipment in home made
boxes made out of copper (you can get small pieces of sheet copper from
the hobby shop). Not cheap, but solders easy and makes a great ground
plane!
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For equipment NOT involving heavy components like large transformers ,you
could consider making a chassis out of (scrap) double sided printed circuit
board material , which is very easy to handle (drill ,cut ,solder) .
Components can be directly soldered to the chassis and RF screens of the
same material can be readily added.
When screening sections ,feed-through capacitors can be easily soldered .
Over the years I bought cut-offs up to large sheets of double sided PCB (at
amateur radio flea markets) , which can also be used to make front panels
and small cabinets/ enclosures.

Frank GM0CSZ / KN6WH