Hey! I've got one of those lurking in my MIDI trinkets box (along with a MIDI solutions MIDI Merge, and plans for my ill fated home built MIDI patch changer*) Ah yes, the days when I patched together my Yamaha clavinova, Yamaha TG01 and Casio VZ1 - Oh what a swanky live rig I thought I had!

*Actually now, in the days of Arduino and Raspberry Pi, I suspect my gadget would be relatively easy now to implement - I wanted a thingy that stored the set list by name and at the touch of a button/footpedal burst out a series of patch and bank change messages to multiple keyboards. It's just that now, my Fantom G can do just that