How about Supreme Advocate?  Or Intercessor?

Gary

<snip>
 What would we want such a
person to be called, who speaks on the behalf of the 3000? Propagandist has
some possibly negative connotations that I would think are better avoided,
and who wants to merely ape IBM? Evangelist is already taken by Apple.
Apologist is similarly misunderstood as propagandist.