If there's any truth to this airing in Australia stuff (I wouldn't bet money on it though!), a number of us will be pretty happy. I never could understand how they managed to air the Special so many times there either... they are the only country known to have aired it more than once.
As far as the masters go, there is definitely no "original negative" per se... the masters would be on videotape and not film, since the Holiday Special was filmed on video. Most likely the masters are professional grade U-Matic half-inch tapes. As to what kind of master Lucasfilm has in their archives and what condition it's in, it's hard to say. There was a segment of the Boba Fett cartoon included in one of the documentaries from Episode 2 times ("Bucket Head"), and from the looks of it the quality isn't much better than a decent VHS tape. So if that's the best Lucasfilm has got for their source, that's not too good.
I expect SOMETHING to happen for the 30th anniversary of the Holiday Special, but I'm unsure what it will be. Considering how little really happened for the 30th anniversary of Star Wars (Celebration 4, and then... nothing? The year's almost over and there won't even be any DVD releases this time!), I don't expect much. But who knows? Considering how much Holiday Special-related official product has been coming out lately, there may be some recognition in store for this red-headed stepchild yet...
--SKot