Back in my "GIT" days, a friend of mine had a "Virtuoso".
He could pull some amazing stuff out of it.
Things that you would most probably would use a "Whammy" pedal for today.
But the big problem was, as expected, that you pretty much have to play with your nails, as the
upper frets are really, really tight!
If I remember correctly, didn't SSV have one of these too?
I think I've seen a pic of him with it, and I can swear that I've read it somewhere, how he talked about having to use his nails to play it....