Bob Motyl KK6KMU
This is a great question. I was thinking about what it would take to give a PSK demo without radios. I see that FLDIGI can record the audio and then play it back. I haven't figured it out yet but it may allow you to record QSOs and then play the whole thing back. All you would need would a large screen and a computer. I'm not sure if that is what the function is for.
Let us knw what you come up with.