90 degree Brake Switch Cover OR Banjo Bolt Cover for your master cylinder if you trim the small end off a bit - fits some Brembo brake switches & banjos. Can be used on rear 900SS brake switch or over any master cylinder banjo/brake line, the closest thing I could find. Now you have another option....
The ID of the large end is approx 16mm, the rubber is flexible and can stretch a bit, especially if warmed up first.