Hi, you stoked my interest too.
If you look at
this translated German page, you get a little more info. (Look at the bottom of the "sound" section.)
It seems the funlab was a MIDI interface specifically for Kawai keyboards.
I also found some links to software for K1 patch editor and K4 editor also. Dunno if posting the links will break any rules, so I will refrain. I'm sure you can find them.
Seems it was popular in Germany, so maybe some of our German friends coudl help.
Good luck.
