I’ve found a vendor that can actually fabricate the chassis. ProMetal has a process that I would describe as the Zcorp process, but working directly with metal. They say they can fabricate the chassis and lids in a stainless steel / bronze alloy which has good physical strength. Their max build envelope is 200 mm^3. This would allow for the fabrication of a dodecahedral core about the size of a basketball. The quote they gave me is within my budget. This is the only executable chassis option I have so far, so I am fixing my design on a radius of 100mm. I spoke with Prometal and they mentioned they have a larger format machine, but it’s down for maintenance currently.
I went ahead and ordered two of the lids from the copper coil version of the core. This will give me a feel for the process and material. I will attempt to laser weld the two lids together.