I don't know the details of your glasswork, but hermetic glass-to-metal seals are a well known technology (think thermionic valves). You may be able to use one with a low temperature glass frit seal to your glasswork?
I'd look into this, that is glass to metal sealing, as the best way forward. Old tubes easily accommodated 8 pins and many more for certain types of tubes. You apparently have electronics inside the glass already so adding wires shouldn't be a problem.
Of course doing this isn't easy if you are not familiar with glass work. You may be able to get help from a local glass blower or even somebody working with neon lights. Glass blowers often have been called upon for custom laboratory glass, so it might help to check with a local university or research center.
Of course going this route pretty much makes for a permanent container so that might be an issue. There are other ways to go if you have a two part container, that is a container with a plug or lid.