I received this Sanyo MBC-885 keyboard some time ago and have been on the fence about converting it or not.
FLS are difficult to convert as most of them speak a proprietary protocol; meaning that usually a controller replacement is the way to go, which is what I ended up doing.
I traced out the matrix and it came out at 23 rows and 4 columns. Easily capable of conversion with a teensy++2.
Instead of soldering the wires straight to the PCB I used pin headers meaning that I could move things around without having to solder/de-solder every single time and damaging the pads.
After that it was a case of wiring it all up and building a firmware for the teensy.
Finally I gave the whole board a good clean, sanded and repainted the plate and applied a small about of lube to the switches.
It is now compatible and fully programmable over USB, complete with layers and macros, and I am currently using it to type this
Here are some photos. I have also included the matrix diagram if you would like to do this project yourself.