You can buy brand new stainless steel chassis from Dynakitparts.net also Tube4hifi.
I bought some from dynaco.net last year for my Mk4 mono's.
Dynaco replacement parts & vacuum tube audio amplifier kits from Dynakit (dynakitparts.com)
cheers
STAIN-LESS STEEL.......DYNACO CHASSIS'S......ST-70 and MK III
I need some help getting some custom made stain-less steel chassis made........Of course none of the people selling them retail will tell me anything, and I can't pay list price for them , but I will buy larger amounts of them.....They would be the basic Dynaco style but with different holes......THANKS