stiiiiiiive wrote:Kurzweil K series instruments have featured that since the nineties.
Back in the day, I owned a furniture-cabinet Kurzweil with three pedals, K1000-based (I believe that was the mid/late 80s).
I found it amazing to hold a string chord with the sostenuto (middle) pedal, switch to a piano/ep/etc. patch, and play on top of the chord. The sustain pedal only affected the second timbre, so long as the sostenuto pedal was held. If you were careful, you could keep swapping between the two timbres seamlessly...
There was no complicated setup to accomplish this, it was baked into the OS. It wasn't even formally documented, it was more of an "Easter egg".