Never seen anything like that before...
 
http://cgi.ebay.com/Alembic-Distillate-Bass-1981-4-5-string-rare-/260695855378?pt=Guitar&hash=item3cb2af1112

I'll 2nd that...

Strange and brilliant,
...just gotta really watch those low ceilings.

Description said this modify was done by Alembic factory.
Hum... tuner on the top of the head

I believe there was a Spoiler that this had this done that showed up a few years back. The tuner was in the same place, if I recall

This my bass, the mod is authentic. I've added a note on the listing about this and a picture of the original work order.

I remember seeing a drawing around here for this before.  
 
This won't work on a Spoiler cone peghead, but if the Spoiler had a Crown peghead then it will work.

Someething about that bass calls to mind a Hemingway polydactyl cat with seven toes on each foot.