This is the case I bought. The back is not configured like the Eval board, so it will have to be replaced, but it should be long enough. If I just have a CAD file for a back, I could probably find a vendor PDQ.
Given how well the Eval 1 version tested, I don't see a need for a custom buffer. I think (pls tell me if I am wrong) plug this straight into a single Smps1200A400 PSU, and have a complete, well functioning amp. Can probably do it for around $1000 USD given I already have the case.
https://www.ghentaudio.com/kit/ncore-se-300w.html