Cool story - as you may also know, 4K isn't that much compared to 80s prices. The Apple II cost close to 7K in today's dollars. The Apple Lisa would set you back 35K in today's dollars.
Lisa had an early capacitance keyboard sensitive to EMF. Our building was next to an AM radio station transmitter and talking or music resulted in a steam of ghost characters when you held your hand over it. For demoing the machine I had a ground wire running to an elbow rest and chair bottom. To type comfortably with no ghost I had to have a bare foot resting on the chair legs.