I've just noticed that Leung Ting is not calling himself a Great Grandmaster (GGM). Since the title itself just sounds silly, I'm assuming he's doing this in an attempt to 'one-up' William Cheung in their seemingly endless feud.

Cthulhu

A Yahoo! search for "Great Grandmaster" returns many martial arts hits. Just one example:
http://www.malaysia.net/people/malaysiawushu/gmaster.html