TMS1400 is derived from TMS1100. If we have a decap of it, it should be fairly easy to emulate. I'd suggest starting with a straightforward 1-chip device, like a calculator.

S&S-related: I'll start on 'extracting' the ROM from the language tutor patent. All those 1s and 0s may look dazzling, but it should be a fun side project making a custom helper tool to read it out.