Well Uncle Dave,
I thought we were actually discussing Technic Hard drives when I made my comment on "who needs one, when you have an sd card".
Admittedly I'd need quite a few sd cards if I wanted to store 5000 mp3's on them, but I personally don't have the need for that amount of mp3's ( I don't perform, I'm only a nutty hobbyist).
There again, I suppose one way around it if I was a performer(why oh why, was I given the talent to make teddy bears instead of music (boohoo) would be to , just copy the mp3's I'd be likely to use for a performance to sdcard, pack up the trusty ol' kn7 along with the sd cards, leave the computer and any other keyboards I'd normally have to drag along at home.
As the kn plays mp3's, if I wanted to use backing tracks from other keyboards ( like my va7 or my ex 9000pro) I'd just record them as mp3's , save to sd card, heck, if I could sing I could even back my own vocals up and save as mp3 to sd card. I'd really only need the one keyboard on stage my trusty old kn7, capable of playing mp3's , mp3's in sync with sequencer files, sequencer files & midifiles. Boy, really makes me wish I was talented enough to perform ( haahaa)

Actually sounds like your beloved korgs maybe starting to go the same way (mp3's & memory cards?)

best wishes
Rikki