I dug out Klaus Blasquiz's book on Fender basses when I was back home over the last few days. The book has a picture of a 5-string Performer prototype, which is quite interesting has it has a third pickup, butting right up against the bridge. The headstock on it looked quite clumsy. The bass was pictured on a page of other Fender odds and sods, including a headless design that had a body similar to the Martin-18 with two pickups that look like Dimarzio Model Gs, and another model that had a headstock like a garden hoe.
The weirdest part for me is that Klaus Blasquiz sang with the French band Magma, who were like Carl Orff and Earth Wind and Fire, combined with abstract occult and Nazi-mysticism imagery, and who sang in a fictional language called Kobaian. Not the first guy I would consider up for documenting Fender bass designs.
Klaus is the long haired guy at the front: