for the most part translations would either use the parent board, or the next larger board in series. You've seen Overload's PCB documentation. You know quite well that most boards are simply part of a series that handle progressively larger ROM and SRAM smile

(For real fun, try Front Mission's fan translation. That makes assumptions that wouldn't work on a cheap PCB)*

* The 32 Mbit patch wouldn't need special mapping hardware, only the original patch would.