There’s a rather jaundiced looking Floyd Rose himself promoting the Floyd Rose Sustainer, a Kramer exclusive. You guessed it: The device has a web page devoted to it, which says:
The neck pickup humbucker actually doubled as a built-in Ebow type unit. Developed by Floyd Rose, Rick Knotts and Steve Moore, the unit yielded a magnetic force that caused the string to vibrate(sustain) infinately (sic).
Read more right here.
Taken from Guitar for the Practicing Musician, January 1989.