I just had a eureka moment.
Preparing notes for the EPROM project I had a look at the schematics and then it hit me.
Practical problem with EPROM emulation are the 2-byte wide parallel interface needed.
What if we skip that side of the memory control and let the clock on the voice card simply control a modern serial EEPROM, or better - a (micro)SD memory card?
Write up and notes on its way, updated frequently so for those interested please refresh. And as always, corrections and direction are welcome.
http://snw.lonningdal.no/sds7eprom.php#sd
--hans