There are smaller capacity makers to consider.  Quality Cartridge (in Maryland) has produced some odd stuff in the past.  I have 3 boxes of 8.15x46R.  Their website says they will make several odd calibers when they get enough backorders.

Starline have said they won't produce bottleneck cases (too many additional steps in production) but they are supposed to have some sort of .405 Winchester basic case in the works.  The demand is for .40-70 Sharps Straight, which was made from .30-40 Krag cases.  We would need to buy forming dies.

Captech International (used to be Jamison) is also doing something with the .405 Basic case.

I think Quality Cartridge is our best bet.