Mike Willinger is a busy webber and has set up loads of Ducati information including sound files to chill the blood; collected introductions from some of the list subscribers and the Desmo Shrine.
Tom Rolland makes brass and silver belt buckles based on a copy of a clutch inspection cover from a Ducati single. I can personally attest to the beauty of these buckles as Tom was kind enough to send me one for running the list.
David Grant has some interesting stuff on his motorycle pages including exploded diagrams and parts catalogue for the Darmah.
Phil Hitchcock runs Road and Race in Australia, he specialises in spares for Italian vintage motorcycles.
Michael Moore runs Euro Spares in San Francisco. As well as the motorcycle electronics and books he sells there is all sorts of other information there particularly on racing chassis design and fabrication.