May be of interest. Found this while looking for info on my K5000S. They did a great job making memory expansions for that keyboard. They're now doing Emu Flash memory:
Update 16.2.2012
I have ordered a sample PCB. It contains the new ME-1, and also my latest project. A flash SIMM memory board with 2MB flash ROM. This will be used for EMU samplers to perform a OS upgrade from V3.xx to V4.xx. Most EMU samplers actually have 1MB flash ROM, however OS V4.xx needs 2MB.
http://www.marjorie.de/kawai/kawai40.htm