I must admit this is a tip-off from a friend. I saw the latest Harry Potter movie last night and didn't notice, but a friend who saw it today reckons that the band playing in the ball scene (including Jarvis Cocker and Steve Mackey from Pulp, Jonny Greenwood and Phil Selway from Radiohead) are using a three-string Walkingstick bass.
Hi Andrew! I have sold 2 Walkingsticks to people in England. Have not heard that they were wizards, however. I do recall seeing a stick bass in the movie, but didn't get a very good look at it. Please let me know if anyone can confirm the sighting... Aloha, -Konabob